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l2tpns/ppp.c
fendo 4ac1a26396 Fix possible IPv6 spoofing
2013-03-17 20:14:05 +01:00

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// L2TPNS PPP Stuff
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include "l2tpns.h"
#include "constants.h"
#include "plugin.h"
#include "util.h"
#include "tbf.h"
#include "cluster.h"
#ifdef LAC
#include "l2tplac.h"
#endif
#include "pppoe.h"
extern tunnelt *tunnel;
extern bundlet *bundle;
extern fragmentationt *frag;
extern sessiont *session;
extern radiust *radius;
extern int tunfd;
extern char hostname[];
extern uint32_t eth_tx;
extern time_t time_now;
extern uint64_t time_now_ms;
extern configt *config;
static int add_lcp_auth(uint8_t *b, int size, int authtype);
static bundleidt new_bundle(void);
static int epdiscmp(epdist, epdist);
static void setepdis(epdist *, epdist);
static void ipcp_open(sessionidt s, tunnelidt t);
static int first_session_in_bundle(sessionidt s)
{
bundleidt i;
for (i = 1; i < MAXBUNDLE; i++)
if (bundle[i].state != BUNDLEFREE)
if (epdiscmp(session[s].epdis,bundle[i].epdis) && !strcmp(session[s].user, bundle[i].user))
return 0;
return 1;
}
// Process PAP messages
void processpap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
{
char user[MAXUSER];
char pass[MAXPASS];
uint16_t hl;
uint16_t r;
CSTAT(processpap);
LOG_HEX(5, "PAP", p, l);
if (l < 4)
{
LOG(1, s, t, "Short PAP %u bytes\n", l);
STAT(tunnel_rx_errors);
sessionshutdown(s, "Short PAP packet.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
{
LOG(1, s, t, "Length mismatch PAP %u/%u\n", hl, l);
STAT(tunnel_rx_errors);
sessionshutdown(s, "PAP length mismatch.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
l = hl;
if (*p != 1)
{
LOG(1, s, t, "Unexpected PAP code %d\n", *p);
STAT(tunnel_rx_errors);
sessionshutdown(s, "Unexpected PAP code.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
if (session[s].ppp.phase != Authenticate)
{
LOG(2, s, t, "PAP ignored in %s phase\n", ppp_phase(session[s].ppp.phase));
return;
}
{
uint8_t *b = p;
b += 4;
user[0] = pass[0] = 0;
if (*b && *b < sizeof(user))
{
memcpy(user, b + 1, *b);
user[*b] = 0;
b += 1 + *b;
if (*b && *b < sizeof(pass))
{
memcpy(pass, b + 1, *b);
pass[*b] = 0;
}
}
LOG(3, s, t, "PAP login %s/%s\n", user, pass);
}
#ifdef LAC
if ((!config->disable_lac_func) && lac_conf_forwardtoremotelns(s, user))
{
// Creating a tunnel/session has been started
return;
}
#endif
if (session[s].ip || !(r = radiusnew(s)))
{
// respond now, either no RADIUS available or already authenticated
uint8_t b[MAXETHER];
uint8_t id = p[1];
uint8_t *p = makeppp(b, sizeof(b), 0, 0, s, t, PPPPAP, 0, 0, 0);
if (!p) return;
if (session[s].ip)
*p = 2; // ACK
else
*p = 3; // cant authorise
p[1] = id;
*(uint16_t *) (p + 2) = htons(5); // length
p[4] = 0; // no message
tunnelsend(b, 5 + (p - b), t); // send it
if (session[s].ip)
{
LOG(3, s, t, "Already an IP allocated: %s (%d)\n",
fmtaddr(htonl(session[s].ip), 0), session[s].ip_pool_index);
}
else
{
LOG(1, s, t, "No RADIUS session available to authenticate session...\n");
sessionshutdown(s, "No free RADIUS sessions.", CDN_UNAVAILABLE, TERM_SERVICE_UNAVAILABLE);
}
}
else
{
// Run PRE_AUTH plugins
struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
run_plugins(PLUGIN_PRE_AUTH, &packet);
if (!packet.continue_auth)
{
LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
if (packet.username) free(packet.username);
if (packet.password) free(packet.password);
return;
}
strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
strncpy(radius[r].pass, packet.password, sizeof(radius[r].pass) - 1);
free(packet.username);
free(packet.password);
radius[r].id = p[1];
LOG(3, s, t, "Sending login for %s/%s to RADIUS\n", user, pass);
if ((session[s].mrru) && (!first_session_in_bundle(s)))
radiussend(r, RADIUSJUSTAUTH);
else
radiussend(r, RADIUSAUTH);
}
}
// Process CHAP messages
void processchap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
{
uint16_t r;
uint16_t hl;
CSTAT(processchap);
LOG_HEX(5, "CHAP", p, l);
if (l < 4)
{
LOG(1, s, t, "Short CHAP %u bytes\n", l);
STAT(tunnel_rx_errors);
sessionshutdown(s, "Short CHAP packet.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
{
LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l);
STAT(tunnel_rx_errors);
sessionshutdown(s, "CHAP length mismatch.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
l = hl;
if (*p != 2)
{
LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
STAT(tunnel_rx_errors);
sessionshutdown(s, "CHAP length mismatch.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
if (session[s].ppp.phase != Authenticate)
{
LOG(2, s, t, "CHAP ignored in %s phase\n", ppp_phase(session[s].ppp.phase));
return;
}
r = sess_local[s].radius;
if (!r)
{
LOG(3, s, t, "Unexpected CHAP message\n");
// Some modems (Netgear DM602, possibly others) persist in using CHAP even
// after ACKing our ConfigReq for PAP.
if (sess_local[s].lcp_authtype == AUTHPAP && config->radius_authtypes & AUTHCHAP)
{
sess_local[s].lcp_authtype = AUTHCHAP;
sendchap(s, t);
}
return;
}
if (p[1] != radius[r].id)
{
LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
STAT(tunnel_rx_errors);
sessionshutdown(s, "Unexpected CHAP response ID.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
if (l < 5 || p[4] != 16)
{
LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]);
STAT(tunnel_rx_errors);
sessionshutdown(s, "Bad CHAP response length.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
l -= 5;
p += 5;
if (l < 16 || l - 16 >= sizeof(session[s].user))
{
LOG(1, s, t, "CHAP user too long %d\n", l - 16);
STAT(tunnel_rx_errors);
sessionshutdown(s, "CHAP username too long.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
// Run PRE_AUTH plugins
{
struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
packet.password = calloc(17, 1);
memcpy(packet.password, p, 16);
p += 16;
l -= 16;
packet.username = calloc(l + 1, 1);
memcpy(packet.username, p, l);
#ifdef LAC
if ((!config->disable_lac_func) && lac_conf_forwardtoremotelns(s, packet.username))
{
free(packet.username);
free(packet.password);
// Creating a tunnel/session has been started
return;
}
#endif
run_plugins(PLUGIN_PRE_AUTH, &packet);
if (!packet.continue_auth)
{
LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
if (packet.username) free(packet.username);
if (packet.password) free(packet.password);
return;
}
strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
memcpy(radius[r].pass, packet.password, 16);
free(packet.username);
free(packet.password);
}
radius[r].chap = 1;
LOG(3, s, t, "CHAP login %s\n", session[s].user);
if ((session[s].mrru) && (!first_session_in_bundle(s)))
radiussend(r, RADIUSJUSTAUTH);
else
radiussend(r, RADIUSAUTH);
}
static void dumplcp(uint8_t *p, int l)
{
int x = l - 4;
uint8_t *o = (p + 4);
LOG_HEX(5, "PPP LCP Packet", p, l);
LOG(4, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_code((int)*p), ntohs( ((uint16_t *) p)[1]) );
LOG(4, 0, 0, "Length: %d\n", l);
if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
return;
while (x > 2)
{
int type = o[0];
int length = o[1];
if (length < 2)
{
LOG(4, 0, 0, " Option length is %d...\n", length);
break;
}
if (type == 0)
{
LOG(4, 0, 0, " Option type is 0...\n");
x -= length;
o += length;
continue;
}
switch (type)
{
case 1: // Maximum-Receive-Unit
if (length == 4)
LOG(4, 0, 0, " %s %d\n", ppp_lcp_option(type), ntohs(*(uint16_t *)(o + 2)));
else
LOG(4, 0, 0, " %s odd length %d\n", ppp_lcp_option(type), length);
break;
case 2: // Async-Control-Character-Map
if (length == 6)
{
uint32_t asyncmap = ntohl(*(uint32_t *)(o + 2));
LOG(4, 0, 0, " %s %x\n", ppp_lcp_option(type), asyncmap);
}
else
LOG(4, 0, 0, " %s odd length %d\n", ppp_lcp_option(type), length);
break;
case 3: // Authentication-Protocol
if (length == 4)
{
int proto = ntohs(*(uint16_t *)(o + 2));
LOG(4, 0, 0, " %s 0x%x (%s)\n", ppp_lcp_option(type), proto,
proto == PPPPAP ? "PAP" : "UNSUPPORTED");
}
else if (length == 5)
{
int proto = ntohs(*(uint16_t *)(o + 2));
int algo = *(o + 4);
LOG(4, 0, 0, " %s 0x%x 0x%x (%s)\n", ppp_lcp_option(type), proto, algo,
(proto == PPPCHAP && algo == 5) ? "CHAP MD5" : "UNSUPPORTED");
}
else
LOG(4, 0, 0, " %s odd length %d\n", ppp_lcp_option(type), length);
break;
case 4: // Quality-Protocol
{
uint32_t qp = ntohl(*(uint32_t *)(o + 2));
LOG(4, 0, 0, " %s %x\n", ppp_lcp_option(type), qp);
}
break;
case 5: // Magic-Number
if (length == 6)
{
uint32_t magicno = ntohl(*(uint32_t *)(o + 2));
LOG(4, 0, 0, " %s %x\n", ppp_lcp_option(type), magicno);
}
else
LOG(4, 0, 0, " %s odd length %d\n", ppp_lcp_option(type), length);
break;
case 7: // Protocol-Field-Compression
case 8: // Address-And-Control-Field-Compression
LOG(4, 0, 0, " %s\n", ppp_lcp_option(type));
break;
default:
LOG(2, 0, 0, " Unknown PPP LCP Option type %d\n", type);
break;
}
x -= length;
o += length;
}
}
void lcp_open(sessionidt s, tunnelidt t)
{
// transition to Authentication or Network phase:
session[s].ppp.phase = sess_local[s].lcp_authtype ? Authenticate : Network;
LOG(3, s, t, "LCP: Opened, phase %s\n", ppp_phase(session[s].ppp.phase));
// LCP now Opened
change_state(s, lcp, Opened);
if (session[s].ppp.phase == Authenticate)
{
if (sess_local[s].lcp_authtype == AUTHCHAP)
sendchap(s, t);
}
else
{
if(session[s].bundle == 0 || bundle[session[s].bundle].num_of_links == 1)
{
// This-Layer-Up
sendipcp(s, t);
change_state(s, ipcp, RequestSent);
// move to passive state for IPv6 (if configured), CCP
if (config->ipv6_prefix.s6_addr[0])
change_state(s, ipv6cp, Stopped);
else
change_state(s, ipv6cp, Closed);
change_state(s, ccp, Stopped);
}
else
{
sessionidt first_ses = bundle[session[s].bundle].members[0];
LOG(3, s, t, "MPPP: Skipping IPCP negotiation for session:%d, first session of bundle is:%d\n",s,first_ses);
ipcp_open(s, t);
}
}
}
void lcp_restart(sessionidt s)
{
session[s].ppp.phase = Establish;
// This-Layer-Down
change_state(s, ipcp, Dead);
change_state(s, ipv6cp, Dead);
change_state(s, ccp, Dead);
}
static uint8_t *ppp_conf_rej(sessionidt s, uint8_t *buf, size_t blen, uint16_t mtype,
uint8_t **response, uint8_t *queued, uint8_t *packet, uint8_t *option)
{
if (!*response || **response != ConfigRej)
{
queued = *response = makeppp(buf, blen, packet, 2, s, session[s].tunnel, mtype, 0, 0, 0);
if (!queued)
return 0;
*queued = ConfigRej;
queued += 4;
}
if ((queued - buf + option[1]) > blen)
{
LOG(2, s, session[s].tunnel, "PPP overflow for ConfigRej (proto %u, option %u).\n", mtype, *option);
return 0;
}
memcpy(queued, option, option[1]);
return queued + option[1];
}
static uint8_t *ppp_conf_nak(sessionidt s, uint8_t *buf, size_t blen, uint16_t mtype,
uint8_t **response, uint8_t *queued, uint8_t *packet, uint8_t *option,
uint8_t *value, size_t vlen)
{
int *nak_sent;
switch (mtype)
{
case PPPLCP: nak_sent = &sess_local[s].lcp.nak_sent; break;
case PPPIPCP: nak_sent = &sess_local[s].ipcp.nak_sent; break;
case PPPIPV6CP: nak_sent = &sess_local[s].ipv6cp.nak_sent; break;
default: return 0; // ?
}
if (*response && **response != ConfigNak)
{
if (*nak_sent < config->ppp_max_failure) // reject queued
return queued;
return ppp_conf_rej(s, buf, blen, mtype, response, 0, packet, option);
}
if (!*response)
{
if (*nak_sent >= config->ppp_max_failure)
return ppp_conf_rej(s, buf, blen, mtype, response, 0, packet, option);
queued = *response = makeppp(buf, blen, packet, 2, s, session[s].tunnel, mtype, 0, 0, 0);
if (!queued)
return 0;
(*nak_sent)++;
*queued = ConfigNak;
queued += 4;
}
if ((queued - buf + vlen + 2) > blen)
{
LOG(2, s, session[s].tunnel, "PPP overflow for ConfigNak (proto %u, option %u).\n", mtype, *option);
return 0;
}
*queued++ = *option;
*queued++ = vlen + 2;
memcpy(queued, value, vlen);
return queued + vlen;
}
static void ppp_code_rej(sessionidt s, tunnelidt t, uint16_t proto,
char *pname, uint8_t *p, uint16_t l, uint8_t *buf, size_t size)
{
uint8_t *q;
int mru = session[s].mru;
if (mru < MINMTU) mru = MINMTU;
if (mru > size) mru = size;
l += 4;
if (l > mru) l = mru;
q = makeppp(buf, size, 0, 0, s, t, proto, 0, 0, 0);
if (!q) return;
*q = CodeRej;
*(q + 1) = ++sess_local[s].lcp_ident;
*(uint16_t *)(q + 2) = htons(l);
memcpy(q + 4, p, l - 4);
LOG(2, s, t, "Unexpected %s code %s\n", pname, ppp_code(*p));
LOG(3, s, t, "%s: send %s\n", pname, ppp_code(*q));
if (config->debug > 3) dumplcp(q, l);
tunnelsend(buf, l + (q - buf), t);
}
// Process LCP messages
void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
{
uint8_t b[MAXETHER];
uint8_t *q = NULL;
uint16_t hl;
CSTAT(processlcp);
LOG_HEX(5, "LCP", p, l);
if (l < 4)
{
LOG(1, s, t, "Short LCP %d bytes\n", l);
STAT(tunnel_rx_errors);
return ;
}
if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
{
LOG(1, s, t, "Length mismatch LCP %u/%u\n", hl, l);
STAT(tunnel_rx_errors);
return ;
}
l = hl;
if (session[s].die) // going down...
return;
LOG(((*p == EchoReq || *p == EchoReply) ? 4 : 3), s, t,
"LCP: recv %s\n", ppp_code(*p));
if (config->debug > 3) dumplcp(p, l);
if (*p == ConfigAck)
{
int x = l - 4;
uint8_t *o = (p + 4);
int authtype = 0;
while (x > 2)
{
int type = o[0];
int length = o[1];
if (length == 0 || type == 0 || x < length) break;
switch (type)
{
case 3: // Authentication-Protocol
{
int proto = ntohs(*(uint16_t *)(o + 2));
if (proto == PPPPAP)
authtype = AUTHPAP;
else if (proto == PPPCHAP && *(o + 4) == 5)
authtype = AUTHCHAP;
}
break;
}
x -= length;
o += length;
}
if (!session[s].ip && authtype)
sess_local[s].lcp_authtype = authtype;
switch (session[s].ppp.lcp)
{
case RequestSent:
initialise_restart_count(s, lcp);
change_state(s, lcp, AckReceived);
break;
case AckReceived:
case Opened:
LOG(2, s, t, "LCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
if (session[s].ppp.lcp == Opened)
lcp_restart(s);
sendlcp(s, t);
change_state(s, lcp, RequestSent);
break;
case AckSent:
lcp_open(s, t);
break;
default:
LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
}
}
else if (*p == ConfigReq)
{
int x = l - 4;
uint8_t *o = (p + 4);
uint8_t *response = 0;
static uint8_t asyncmap[4] = { 0, 0, 0, 0 }; // all zero
static uint8_t authproto[5];
int changed = 0;
while (x > 2)
{
int type = o[0];
int length = o[1];
if (length == 0 || type == 0 || x < length) break;
switch (type)
{
case 1: // Maximum-Receive-Unit
{
uint16_t mru = ntohs(*(uint16_t *)(o + 2));
if (mru >= MINMTU)
{
session[s].mru = mru;
changed++;
break;
}
LOG(3, s, t, " Remote requesting MRU of %u. Rejecting.\n", mru);
mru = htons(MRU);
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, (uint8_t *) &mru, sizeof(mru));
}
break;
case 2: // Async-Control-Character-Map
if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
break;
LOG(3, s, t, " Remote requesting asyncmap. Rejecting.\n");
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, asyncmap, sizeof(asyncmap));
break;
case 3: // Authentication-Protocol
{
int proto = ntohs(*(uint16_t *)(o + 2));
char proto_name[] = "0x0000";
int alen;
if (proto == PPPPAP)
{
if (config->radius_authtypes & AUTHPAP)
{
sess_local[s].lcp_authtype = AUTHPAP;
break;
}
strcpy(proto_name, "PAP");
}
else if (proto == PPPCHAP)
{
if (config->radius_authtypes & AUTHCHAP
&& *(o + 4) == 5) // MD5
{
sess_local[s].lcp_authtype = AUTHCHAP;
break;
}
strcpy(proto_name, "CHAP");
}
else
sprintf(proto_name, "%#4.4x", proto);
LOG(3, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name);
alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authprefer);
if (alen < 2) break; // paranoia
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
if (q && *response == ConfigNak &&
config->radius_authtypes != config->radius_authprefer)
{
// alternate type
alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authtypes & ~config->radius_authprefer);
if (alen < 2) break;
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
}
break;
}
break;
case 4: // Quality-Protocol
case 5: // Magic-Number
case 7: // Protocol-Field-Compression
case 8: // Address-And-Control-Field-Compression
break;
case 17: // Multilink Max-Receive-Reconstructed-Unit
{
uint16_t mrru = ntohs(*(uint16_t *)(o + 2));
session[s].mrru = mrru;
changed++;
LOG(3, s, t, " Received PPP LCP option MRRU: %d\n",mrru);
}
break;
case 18: // Multilink Short Sequence Number Header Format
{
session[s].mssf = 1;
changed++;
LOG(3, s, t, " Received PPP LCP option MSSN format\n");
}
break;
case 19: // Multilink Endpoint Discriminator
{
uint8_t epdis_class = o[2];
int addr;
session[s].epdis.addr_class = epdis_class;
session[s].epdis.length = length - 3;
if (session[s].epdis.length > 20)
{
LOG(1, s, t, "Error: received EndDis Address Length more than 20: %d\n", session[s].epdis.length);
session[s].epdis.length = 20;
}
for (addr = 0; addr < session[s].epdis.length; addr++)
session[s].epdis.address[addr] = o[3+addr];
changed++;
switch (epdis_class)
{
case LOCALADDR:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis Local Address Class: %d\n",epdis_class);
break;
case IPADDR:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis IP Address Class: %d\n",epdis_class);
break;
case IEEEMACADDR:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis IEEE MAC Address Class: %d\n",epdis_class);
break;
case PPPMAGIC:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis PPP Magic No Class: %d\n",epdis_class);
break;
case PSNDN:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis PSND No Class: %d\n",epdis_class);
break;
default:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis NULL Class %d\n",epdis_class);
}
}
break;
default: // Reject any unknown options
LOG(3, s, t, " Rejecting unknown PPP LCP option %d\n", type);
q = ppp_conf_rej(s, b, sizeof(b), PPPLCP, &response, q, p, o);
}
x -= length;
o += length;
}
if (changed)
cluster_send_session(s);
if (response)
{
l = q - response; // LCP packet length
*((uint16_t *) (response + 2)) = htons(l); // update header
}
else
{
// Send packet back as ConfigAck
response = makeppp(b, sizeof(b), p, l, s, t, PPPLCP, 0, 0, 0);
if (!response) return;
*response = ConfigAck;
}
switch (session[s].ppp.lcp)
{
case Closed:
response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP, 0, 0, 0);
if (!response) return;
*response = TerminateAck;
*((uint16_t *) (response + 2)) = htons(l = 4);
break;
case Stopped:
initialise_restart_count(s, lcp);
sendlcp(s, t);
if (*response == ConfigAck)
change_state(s, lcp, AckSent);
else
change_state(s, lcp, RequestSent);
break;
case RequestSent:
if (*response == ConfigAck)
change_state(s, lcp, AckSent);
break;
case AckReceived:
if (*response == ConfigAck)
lcp_open(s, t);
break;
case Opened:
lcp_restart(s);
sendlcp(s, t);
/* fallthrough */
case AckSent:
if (*response == ConfigAck)
change_state(s, lcp, AckSent);
else
change_state(s, lcp, RequestSent);
break;
case Closing:
sessionshutdown(s, "LCP: ConfigReq in state Closing. This should not happen. Killing session.", CDN_ADMIN_DISC, TERM_LOST_SERVICE);
break;
default:
LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
return;
}
LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
if (config->debug > 3) dumplcp(response, l);
tunnelsend(b, l + (response - b), t);
}
else if (*p == ConfigNak || *p == ConfigRej)
{
int x = l - 4;
uint8_t *o = (p + 4);
int authtype = -1;
while (x > 2)
{
int type = o[0];
int length = o[1];
if (length == 0 || type == 0 || x < length) break;
switch (type)
{
case 1: // Maximum-Receive-Unit
if (*p == ConfigNak)
{
if (length < 4) break;
sess_local[s].ppp_mru = ntohs(*(uint16_t *)(o + 2));
LOG(3, s, t, " Remote requested MRU of %u\n", sess_local[s].ppp_mru);
}
else
{
sess_local[s].ppp_mru = 0;
LOG(3, s, t, " Remote rejected MRU negotiation\n");
}
break;
case 3: // Authentication-Protocol
if (authtype > 0)
break;
if (*p == ConfigNak)
{
int proto;
if (length < 4) break;
proto = ntohs(*(uint16_t *)(o + 2));
if (proto == PPPPAP)
{
authtype = config->radius_authtypes & AUTHPAP;
LOG(3, s, t, " Remote requested PAP authentication...%sing\n",
authtype ? "accept" : "reject");
}
else if (proto == PPPCHAP && length > 4 && *(o + 4) == 5)
{
authtype = config->radius_authtypes & AUTHCHAP;
LOG(3, s, t, " Remote requested CHAP authentication...%sing\n",
authtype ? "accept" : "reject");
}
else
{
LOG(3, s, t, " Rejecting unsupported authentication %#4x\n",
proto);
}
}
else
{
LOG(2, s, t, "LCP: remote rejected auth negotiation\n");
authtype = 0; // shutdown
}
break;
case 5: // Magic-Number
session[s].magic = 0;
if (*p == ConfigNak)
{
if (length < 6) break;
session[s].magic = ntohl(*(uint32_t *)(o + 2));
}
if (session[s].magic)
LOG(3, s, t, " Remote requested magic-no %x\n", session[s].magic);
else
LOG(3, s, t, " Remote rejected magic-no\n");
cluster_send_session(s);
break;
case 17: // Multilink Max-Receive-Reconstructed-Unit
{
if (*p == ConfigNak)
{
sess_local[s].mp_mrru = ntohs(*(uint16_t *)(o + 2));
LOG(3, s, t, " Remote requested MRRU of %u\n", sess_local[s].mp_mrru);
}
else
{
sess_local[s].mp_mrru = 0;
LOG(3, s, t, " Remote rejected MRRU negotiation\n");
}
}
break;
case 18: // Multilink Short Sequence Number Header Format
{
if (*p == ConfigNak)
{
sess_local[s].mp_mssf = 0;
LOG(3, s, t, " Remote requested Naked mssf\n");
}
else
{
sess_local[s].mp_mssf = 0;
LOG(3, s, t, " Remote rejected mssf\n");
}
}
break;
case 19: // Multilink Endpoint Discriminator
{
if (*p == ConfigNak)
{
LOG(2, s, t, " Remote should not configNak Endpoint Dis!\n");
}
else
{
sess_local[s].mp_epdis = 0;
LOG(3, s, t, " Remote rejected Endpoint Discriminator\n");
}
}
break;
default:
LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
sessionshutdown(s, "Unable to negotiate LCP.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
x -= length;
o += length;
}
if (!authtype)
{
sessionshutdown(s, "Unsupported authentication.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
if (authtype > 0)
sess_local[s].lcp_authtype = authtype;
switch (session[s].ppp.lcp)
{
case Closed:
case Stopped:
{
uint8_t *response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP, 0, 0, 0);
if (!response) return;
*response = TerminateAck;
*((uint16_t *) (response + 2)) = htons(l = 4);
LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
if (config->debug > 3) dumplcp(response, l);
tunnelsend(b, l + (response - b), t);
}
break;
case RequestSent:
case AckSent:
initialise_restart_count(s, lcp);
sendlcp(s, t);
break;
case AckReceived:
LOG(2, s, t, "LCP: ConfigNak in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
sendlcp(s, t);
break;
case Opened:
lcp_restart(s);
sendlcp(s, t);
break;
default:
LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
return;
}
}
else if (*p == TerminateReq)
{
switch (session[s].ppp.lcp)
{
case Closed:
case Stopped:
case Closing:
case Stopping:
case RequestSent:
case AckReceived:
case AckSent:
break;
case Opened:
lcp_restart(s);
zero_restart_count(s, lcp);
change_state(s, lcp, Closing);
break;
default:
LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
return;
}
*p = TerminateAck; // send ack
q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP, 0, 0, 0);
if (!q) return;
LOG(3, s, t, "LCP: send %s\n", ppp_code(*q));
if (config->debug > 3) dumplcp(q, l);
tunnelsend(b, l + (q - b), t); // send it
}
else if (*p == ProtocolRej)
{
uint16_t proto = 0;
if (l > 4)
{
proto = *(p+4);
if (l > 5 && !(proto & 1))
{
proto <<= 8;
proto |= *(p+5);
}
}
if (proto == PPPIPV6CP)
{
LOG(3, s, t, "IPv6 rejected\n");
change_state(s, ipv6cp, Closed);
}
else
{
LOG(3, s, t, "LCP protocol reject: 0x%04X\n", proto);
}
}
else if (*p == EchoReq)
{
*p = EchoReply; // reply
*(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP, 0, 0, 0);
if (!q) return;
LOG(4, s, t, "LCP: send %s\n", ppp_code(*q));
if (config->debug > 3) dumplcp(q, l);
tunnelsend(b, l + (q - b), t); // send it
}
else if (*p == EchoReply)
{
// Ignore it, last_packet time is set earlier than this.
}
else if (*p != CodeRej)
{
ppp_code_rej(s, t, PPPLCP, "LCP", p, l, b, sizeof(b));
}
}
int join_bundle(sessionidt s)
{
// Search for a bundle to join
bundleidt i;
bundleidt b;
for (i = 1; i < MAXBUNDLE; i++)
{
if (bundle[i].state != BUNDLEFREE)
{
if (epdiscmp(session[s].epdis,bundle[i].epdis) && !strcmp(session[s].user, bundle[i].user))
{
sessionidt first_ses = bundle[i].members[0];
if (bundle[i].mssf != session[s].mssf)
{
// uniformity of sequence number format must be insured
LOG(3, s, session[s].tunnel, "MPPP: unable to bundle session %d in bundle %d cause of different mssf\n", s, i);
return -1;
}
session[s].bundle = i;
session[s].ip = session[first_ses].ip;
session[s].dns1 = session[first_ses].dns1;
session[s].dns2 = session[first_ses].dns2;
session[s].timeout = session[first_ses].timeout;
if(session[s].epdis.length > 0)
setepdis(&bundle[i].epdis, session[s].epdis);
strcpy(bundle[i].user, session[s].user);
bundle[i].members[bundle[i].num_of_links] = s;
bundle[i].num_of_links++;
LOG(3, s, session[s].tunnel, "MPPP: Bundling additional line in bundle (%d), lines:%d\n",i,bundle[i].num_of_links);
return i;
}
}
}
// No previously created bundle was found for this session, so create a new one
if (!(b = new_bundle())) return 0;
session[s].bundle = b;
bundle[b].mrru = session[s].mrru;
bundle[b].mssf = session[s].mssf;
// FIXME !!! to enable l2tpns reading mssf frames receiver_max_seq, sender_max_seq must be introduce
// now session[s].mssf flag indecates that the receiver wish to receive frames in mssf, so max_seq (i.e. recv_max_seq) = 1<<24
/*
if (bundle[b].mssf)
bundle[b].max_seq = 1 << 12;
else */
bundle[b].max_seq = 1 << 24;
if(session[s].epdis.length > 0)
setepdis(&bundle[b].epdis, session[s].epdis);
strcpy(bundle[b].user, session[s].user);
bundle[b].members[0] = s;
bundle[b].timeout = session[s].timeout;
LOG(3, s, session[s].tunnel, "MPPP: Created a new bundle (%d)\n", b);
return b;
}
static int epdiscmp(epdist ep1, epdist ep2)
{
int ad;
if (ep1.length != ep2.length)
return 0;
if (ep1.addr_class != ep2.addr_class)
return 0;
for (ad = 0; ad < ep1.length; ad++)
if (ep1.address[ad] != ep2.address[ad])
return 0;
return 1;
}
static void setepdis(epdist *ep1, epdist ep2)
{
int ad;
ep1->length = ep2.length;
ep1->addr_class = ep2.addr_class;
for (ad = 0; ad < ep2.length; ad++)
ep1->address[ad] = ep2.address[ad];
}
static bundleidt new_bundle()
{
bundleidt i;
for (i = 1; i < MAXBUNDLE; i++)
{
if (bundle[i].state == BUNDLEFREE)
{
LOG(4, 0, 0, "MPPP: Assigning bundle ID %d\n", i);
bundle[i].num_of_links = 1;
bundle[i].last_check = time_now; // Initialize last_check value
bundle[i].state = BUNDLEOPEN;
bundle[i].current_ses = -1; // This is to enforce the first session 0 to be used at first
memset(&frag[i], 0, sizeof(fragmentationt));
if (i > config->cluster_highest_bundleid)
config->cluster_highest_bundleid = i;
return i;
}
}
LOG(0, 0, 0, "MPPP: Can't find a free bundle! There shouldn't be this many in use!\n");
return 0;
}
static void ipcp_open(sessionidt s, tunnelidt t)
{
LOG(3, s, t, "IPCP: Opened, session is now active\n");
change_state(s, ipcp, Opened);
if (!(session[s].walled_garden || session[s].flags & SESSION_STARTED))
{
uint16_t r = radiusnew(s);
if (r)
{
radiussend(r, RADIUSSTART); // send radius start
// don't send further Start records if IPCP is restarted
session[s].flags |= SESSION_STARTED;
cluster_send_session(s);
}
}
// start IPv6 if configured and still in passive state
if (session[s].ppp.ipv6cp == Stopped)
{
sendipv6cp(s, t);
change_state(s, ipv6cp, RequestSent);
}
}
// Process IPCP messages
void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
{
uint8_t b[MAXETHER];
uint8_t *q = 0;
uint16_t hl;
CSTAT(processipcp);
LOG_HEX(5, "IPCP", p, l);
if (l < 4)
{
LOG(1, s, t, "Short IPCP %d bytes\n", l);
STAT(tunnel_rx_errors);
return ;
}
if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
{
LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
STAT(tunnel_rx_errors);
return ;
}
l = hl;
if (session[s].ppp.phase < Network)
{
LOG(2, s, t, "IPCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
return;
}
LOG(3, s, t, "IPCP: recv %s\n", ppp_code(*p));
if (*p == ConfigAck)
{
switch (session[s].ppp.ipcp)
{
case RequestSent:
initialise_restart_count(s, ipcp);
change_state(s, ipcp, AckReceived);
break;
case AckReceived:
case Opened:
LOG(2, s, t, "IPCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ipcp));
sendipcp(s, t);
change_state(s, ipcp, RequestSent);
break;
case AckSent:
ipcp_open(s, t);
break;
default:
LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
}
}
else if (*p == ConfigReq)
{
uint8_t *response = 0;
uint8_t *o = p + 4;
int length = l - 4;
int gotip = 0;
in_addr_t addr;
while (length > 2)
{
if (!o[1] || o[1] > length) return;
switch (*o)
{
case 3: // ip address
gotip++; // seen address
if (o[1] != 6) return;
addr = htonl(session[s].ip);
if (memcmp(o + 2, &addr, (sizeof addr)))
{
uint8_t *oq = q;
q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
if (!q || (q != oq && *response == ConfigRej))
{
sessionshutdown(s, "Can't negotiate IPCP.", CDN_ADMIN_DISC, TERM_USER_ERROR);
return;
}
}
break;
case 129: // primary DNS
if (o[1] != 6) return;
addr = htonl(session[s].dns1);
if (memcmp(o + 2, &addr, (sizeof addr)))
{
q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
if (!q) return;
}
break;
case 131: // secondary DNS
if (o[1] != 6) return;
addr = htonl(session[s].dns2);
if (memcmp(o + 2, &addr, sizeof(addr)))
{
q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
if (!q) return;
}
break;
default:
LOG(2, s, t, " Rejecting PPP IPCP Option type %d\n", *o);
q = ppp_conf_rej(s, b, sizeof(b), PPPIPCP, &response, q, p, o);
if (!q) return;
}
length -= o[1];
o += o[1];
}
if (response)
{
l = q - response; // IPCP packet length
*((uint16_t *) (response + 2)) = htons(l); // update header
}
else if (gotip)
{
// Send packet back as ConfigAck
response = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP, 0, 0, 0);
if (!response) return;
*response = ConfigAck;
}
else
{
LOG(1, s, t, "No IP in IPCP request\n");
STAT(tunnel_rx_errors);
return;
}
switch (session[s].ppp.ipcp)
{
case Closed:
response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPCP, 0, 0, 0);
if (!response) return;
*response = TerminateAck;
*((uint16_t *) (response + 2)) = htons(l = 4);
break;
case Stopped:
initialise_restart_count(s, ipcp);
sendipcp(s, t);
if (*response == ConfigAck)
change_state(s, ipcp, AckSent);
else
change_state(s, ipcp, RequestSent);
break;
case RequestSent:
if (*response == ConfigAck)
change_state(s, ipcp, AckSent);
break;
case AckReceived:
if (*response == ConfigAck)
ipcp_open(s, t);
break;
case Opened:
initialise_restart_count(s, ipcp);
sendipcp(s, t);
/* fallthrough */
case AckSent:
if (*response == ConfigAck)
change_state(s, ipcp, AckSent);
else
change_state(s, ipcp, RequestSent);
break;
default:
LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
return;
}
LOG(3, s, t, "IPCP: send %s\n", ppp_code(*response));
tunnelsend(b, l + (response - b), t);
}
else if (*p == TerminateReq)
{
switch (session[s].ppp.ipcp)
{
case Closed:
case Stopped:
case Closing:
case Stopping:
case RequestSent:
case AckReceived:
case AckSent:
break;
case Opened:
zero_restart_count(s, ipcp);
change_state(s, ipcp, Closing);
break;
default:
LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
return;
}
*p = TerminateAck; // send ack
q = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP, 0, 0, 0);
if (!q) return;
LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
tunnelsend(b, l + (q - b), t); // send it
}
else if (*p != CodeRej)
{
ppp_code_rej(s, t, PPPIPCP, "IPCP", p, l, b, sizeof(b));
}
}
static void ipv6cp_open(sessionidt s, tunnelidt t)
{
LOG(3, s, t, "IPV6CP: Opened\n");
change_state(s, ipv6cp, Opened);
if (session[s].ipv6prefixlen)
route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
// Send an initial RA (TODO: Should we send these regularly?)
send_ipv6_ra(s, t, NULL);
}
// Process IPV6CP messages
void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
{
uint8_t b[MAXETHER];
uint8_t *q = 0;
uint16_t hl;
CSTAT(processipv6cp);
LOG_HEX(5, "IPV6CP", p, l);
if (l < 4)
{
LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
STAT(tunnel_rx_errors);
return ;
}
if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
{
LOG(1, s, t, "Length mismatch IPV6CP %u/%u\n", hl, l);
STAT(tunnel_rx_errors);
return ;
}
l = hl;
if (session[s].ppp.phase < Network)
{
LOG(2, s, t, "IPV6CP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
return;
}
LOG(3, s, t, "IPV6CP: recv %s\n", ppp_code(*p));
if (!session[s].ip)
{
LOG(3, s, t, "IPV6CP: no IPv4 address (IPCP in state %s)\n", ppp_state(session[s].ppp.ipcp));
return; // need IPCP to complete...
}
if (*p == ConfigAck)
{
switch (session[s].ppp.ipv6cp)
{
case RequestSent:
initialise_restart_count(s, ipv6cp);
change_state(s, ipv6cp, AckReceived);
break;
case AckReceived:
case Opened:
LOG(2, s, t, "IPV6CP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ipv6cp));
sendipv6cp(s, t);
change_state(s, ipv6cp, RequestSent);
break;
case AckSent:
ipv6cp_open(s, t);
break;
default:
LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
}
}
else if (*p == ConfigReq)
{
uint8_t *response = 0;
uint8_t *o = p + 4;
int length = l - 4;
int gotip = 0;
uint32_t ident[2];
while (length > 2)
{
if (!o[1] || o[1] > length) return;
switch (*o)
{
case 1: // interface identifier
gotip++; // seen address
if (o[1] != 10) return;
ident[0] = htonl(session[s].ip);
ident[1] = 0;
if (memcmp(o + 2, ident, sizeof(ident)))
{
q = ppp_conf_nak(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o, (uint8_t *)ident, sizeof(ident));
if (!q) return;
}
break;
default:
LOG(2, s, t, " Rejecting PPP IPV6CP Option type %d\n", *o);
q = ppp_conf_rej(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o);
if (!q) return;
}
length -= o[1];
o += o[1];
}
if (response)
{
l = q - response; // IPV6CP packet length
*((uint16_t *) (response + 2)) = htons(l); // update header
}
else if (gotip)
{
// Send packet back as ConfigAck
response = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP, 0, 0, 0);
if (!response) return;
*response = ConfigAck;
}
else
{
LOG(1, s, t, "No interface identifier in IPV6CP request\n");
STAT(tunnel_rx_errors);
return;
}
switch (session[s].ppp.ipv6cp)
{
case Closed:
response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPV6CP, 0, 0, 0);
if (!response) return;
*response = TerminateAck;
*((uint16_t *) (response + 2)) = htons(l = 4);
break;
case Stopped:
initialise_restart_count(s, ipv6cp);
sendipv6cp(s, t);
if (*response == ConfigAck)
change_state(s, ipv6cp, AckSent);
else
change_state(s, ipv6cp, RequestSent);
break;
case RequestSent:
if (*response == ConfigAck)
change_state(s, ipv6cp, AckSent);
break;
case AckReceived:
if (*response == ConfigAck)
ipv6cp_open(s, t);
break;
case Opened:
initialise_restart_count(s, ipv6cp);
sendipv6cp(s, t);
/* fallthrough */
case AckSent:
if (*response == ConfigAck)
change_state(s, ipv6cp, AckSent);
else
change_state(s, ipv6cp, RequestSent);
break;
default:
LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
return;
}
LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*response));
tunnelsend(b, l + (response - b), t);
}
else if (*p == TerminateReq)
{
switch (session[s].ppp.ipv6cp)
{
case Closed:
case Stopped:
case Closing:
case Stopping:
case RequestSent:
case AckReceived:
case AckSent:
break;
case Opened:
zero_restart_count(s, ipv6cp);
change_state(s, ipv6cp, Closing);
break;
default:
LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
return;
}
*p = TerminateAck; // send ack
q = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP, 0, 0, 0);
if (!q) return;
LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
tunnelsend(b, l + (q - b), t); // send it
}
else if (*p != CodeRej)
{
ppp_code_rej(s, t, PPPIPV6CP, "IPV6CP", p, l, b, sizeof(b));
}
}
static void update_sessions_in_stat(sessionidt s, uint16_t l)
{
bundleidt b = session[s].bundle;
if (!b)
{
increment_counter(&session[s].cin, &session[s].cin_wrap, l);
session[s].cin_delta += l;
session[s].pin++;
sess_local[s].cin += l;
sess_local[s].pin++;
}
else
{
int i = frag[b].re_frame_begin_index;
int end = frag[b].re_frame_end_index;
for (;;)
{
l = frag[b].fragment[i].length;
s = frag[b].fragment[i].sid;
increment_counter(&session[s].cin, &session[s].cin_wrap, l);
session[s].cin_delta += l;
session[s].pin++;
sess_local[s].cin += l;
sess_local[s].pin++;
if (i == end)
return;
i = (i + 1) & MAXFRAGNUM_MASK;
}
}
}
// process IP packet received
//
// This MUST be called with at least 4 byte behind 'p'.
// (i.e. this routine writes to p[-4]).
void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
{
in_addr_t ip;
CSTAT(processipin);
LOG_HEX(5, "IP", p, l);
if (l < 20)
{
LOG(1, s, t, "IP packet too short %d\n", l);
STAT(tunnel_rx_errors);
return ;
}
ip = ntohl(*(uint32_t *)(p + 12));
if (l > MAXETHER)
{
LOG(1, s, t, "IP packet too long %d\n", l);
STAT(tunnel_rx_errors);
return ;
}
if (session[s].ppp.phase != Network || session[s].ppp.ipcp != Opened)
return;
if (!session[s].bundle || bundle[session[s].bundle].num_of_links < 2) // FIXME:
{
// no spoof (do sessionbyip to handled statically routed subnets)
if (!config->disable_no_spoof && ip != session[s].ip && sessionbyip(htonl(ip)) != s)
{
LOG(4, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
return;
}
}
// run access-list if any
if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
return;
// adjust MSS on SYN and SYN,ACK packets with options
if ((ntohs(*(uint16_t *) (p + 6)) & 0x1fff) == 0 && p[9] == IPPROTO_TCP) // first tcp fragment
{
int ihl = (p[0] & 0xf) * 4; // length of IP header
if (l >= ihl + 20 && (p[ihl + 13] & TCP_FLAG_SYN) && ((p[ihl + 12] >> 4) > 5))
adjust_tcp_mss(s, t, p, l, p + ihl);
}
// Add on the tun header
p -= 4;
*(uint32_t *) p = htonl(PKTIP);
l += 4;
if (session[s].tbf_in)
{
// Are we throttling this session?
if (config->cluster_iam_master)
tbf_queue_packet(session[s].tbf_in, p, l);
else
master_throttle_packet(session[s].tbf_in, p, l);
return;
}
// send to ethernet
if (tun_write(p, l) < 0)
{
STAT(tun_tx_errors);
LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
l, strerror(errno), tunfd, p);
return;
}
p += 4;
l -= 4;
if (session[s].snoop_ip && session[s].snoop_port)
{
// Snooping this session
snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
}
update_sessions_in_stat(s, l);
eth_tx += l;
STAT(tun_tx_packets);
INC_STAT(tun_tx_bytes, l);
}
// process Multilink PPP packet received
void processmpin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
{
bundleidt b = session[s].bundle;
bundlet * this_bundle = &bundle[b];
uint32_t maskSeq, max_seq;
int frag_offset;
uint16_t frag_index, frag_index_next, frag_index_prev;
fragmentationt *this_fragmentation = &frag[b];
uint8_t begin_frame = (*p & MP_BEGIN);
uint8_t end_frame = (*p & MP_END);
uint32_t seq_num, seq_num_next, seq_num_prev;
uint32_t i;
uint8_t flags = *p;
uint16_t begin_index, end_index;
// Perform length checking
if(l > MAXFRAGLEN)
{
LOG(2, s, t, "MPPP: discarding fragment larger than MAXFRAGLEN\n");
return;
}
if(!b)
{
LOG(2, s, t, "MPPP: Invalid bundle id: 0\n");
return;
}
// FIXME !! session[s].mssf means that the receiver wants to receive frames in mssf not means the receiver will send frames in mssf
/* if(session[s].mssf)
{
// Get 12 bit for seq number
seq_num = ntohs((*(uint16_t *) p) & 0xFF0F);
p += 2;
l -= 2;
// After this point the pointer should be advanced 2 bytes
LOG(3, s, t, "MPPP: 12 bits, sequence number: %d\n",seq_num);
}
else */
{
// Get 24 bit for seq number
seq_num = ntohl((*(uint32_t *) p) & 0xFFFFFF00);
p += 4;
l -= 4;
// After this point the pointer should be advanced 4 bytes
LOG(4, s, t, "MPPP: 24 bits sequence number:%d\n",seq_num);
}
max_seq = this_bundle->max_seq;
maskSeq = max_seq - 1;
/*
* Expand sequence number to 32 bits, making it as close
* as possible to this_fragmentation->M.
*/
seq_num |= this_fragmentation->M & ~maskSeq;
if ((int)(this_fragmentation->M - seq_num) > (int)(maskSeq >> 1))
{
seq_num += maskSeq + 1;
}
else if ((int)(seq_num - this_fragmentation->M) > (int)(maskSeq >> 1))
{
seq_num -= maskSeq + 1; /* should never happen */
}
// calculate this fragment's offset from the begin seq in the bundle
frag_offset = (int) (seq_num - this_fragmentation->start_seq);
sess_local[s].last_seq = seq_num;
// calculate the jitter average
uint32_t ljitter = time_now_ms - sess_local[s].prev_time;
if (ljitter > 0)
{
sess_local[s].jitteravg = (sess_local[s].jitteravg + ljitter)>>1;
sess_local[s].prev_time = time_now_ms;
}
uint32_t Mmin;
if (seq_num < this_fragmentation->M)
{
Mmin = seq_num;
this_fragmentation->M = seq_num;
}
else
{
Mmin = sess_local[(this_bundle->members[0])].last_seq;
for (i = 1; i < this_bundle->num_of_links; i++)
{
uint32_t s_seq = sess_local[(this_bundle->members[i])].last_seq;
if (s_seq < Mmin)
Mmin = s_seq;
}
this_fragmentation->M = Mmin;
}
// calculate M offset of the M seq in the bundle
int M_offset = (int) (Mmin - this_fragmentation->start_seq);
if (M_offset >= MAXFRAGNUM)
{
// There have a long break of the link !!!!!!!!
// M_offset is bigger that the fragmentation buffer size
LOG(3, s, t, "MPPP: M_offset out of range, min:%d, begin_seq:%d\n", Mmin, this_fragmentation->start_seq);
// Calculate the new start index, the previous frag are lost
begin_index = (M_offset + this_fragmentation->start_index) & MAXFRAGNUM_MASK;
// Set new Start sequence
this_fragmentation->start_index = begin_index;
this_fragmentation->start_seq = Mmin;
M_offset = 0;
// recalculate the fragment offset from the new begin seq in the bundle
frag_offset = (int) (seq_num - Mmin);
}
// discard this fragment if the packet comes before the start sequence
if (frag_offset < 0)
{
// this packet comes before the next
LOG(3, s, t, "MPPP: (COMES BEFORE) the next, seq:%d, begin_seq:%d, size_frag:%d, flags:%02X is LOST\n", seq_num, this_fragmentation->start_seq, l, flags);
return;
}
// discard if frag_offset is bigger that the fragmentation buffer size
if (frag_offset >= MAXFRAGNUM)
{
// frag_offset is bigger that the fragmentation buffer size
LOG(3, s, t, "MPPP: Index out of range, seq:%d, begin_seq:%d\n", seq_num, this_fragmentation->start_seq);
return;
}
//caculate received fragment's index in the fragment array
frag_index = (frag_offset + this_fragmentation->start_index) & MAXFRAGNUM_MASK;
// insert the frame in it's place
fragmentt *this_frag = &this_fragmentation->fragment[frag_index];
if (this_frag->length > 0)
// This fragment is lost, It was around the buffer and it was never completed the packet.
LOG(3, this_frag->sid, this_frag->tid, "MPPP: (INSERT) seq_num:%d frag_index:%d flags:%02X is LOST\n",
this_frag->seq, frag_index, this_frag->flags);
this_frag->length = l;
this_frag->sid = s;
this_frag->tid = t;
this_frag->flags = flags;
this_frag->seq = seq_num;
this_frag->jitteravg = sess_local[s].jitteravg;
memcpy(this_frag->data, p, l);
LOG(4, s, t, "MPPP: seq_num:%d frag_index:%d INSERTED flags: %02X\n", seq_num, frag_index, flags);
//next frag index
frag_index_next = (frag_index + 1) & MAXFRAGNUM_MASK;
//previous frag index
frag_index_prev = (frag_index - 1) & MAXFRAGNUM_MASK;
// next seq
seq_num_next = seq_num + 1;
// previous seq
seq_num_prev = seq_num - 1;
// Clean the buffer and log the lost fragments
if ((frag_index_next != this_fragmentation->start_index) && this_fragmentation->fragment[frag_index_next].length)
{
// check if the next frag is a lost fragment
if (this_fragmentation->fragment[frag_index_next].seq != seq_num_next)
{
// This fragment is lost, It was around the buffer and it was never completed the packet.
LOG(3, this_fragmentation->fragment[frag_index_next].sid, this_fragmentation->fragment[frag_index_next].tid,
"MPPP: (NEXT) seq_num:%d frag_index:%d flags:%02X is LOST\n",
this_fragmentation->fragment[frag_index_next].seq, frag_index_next,
this_fragmentation->fragment[frag_index_next].flags);
// this frag is lost
this_fragmentation->fragment[frag_index_next].length = 0;
this_fragmentation->fragment[frag_index_next].flags = 0;
if (begin_frame && (!end_frame)) return; // assembling frame failed
}
}
// Clean the buffer and log the lost fragments
if ((frag_index != this_fragmentation->start_index) && this_fragmentation->fragment[frag_index_prev].length)
{
// check if the next frag is a lost fragment
if (this_fragmentation->fragment[frag_index_prev].seq != seq_num_prev)
{
// This fragment is lost, It was around the buffer and it was never completed the packet.
LOG(3, this_fragmentation->fragment[frag_index_prev].sid, this_fragmentation->fragment[frag_index_prev].tid,
"MPPP: (PREV) seq_num:%d frag_index:%d flags:%02X is LOST\n",
this_fragmentation->fragment[frag_index_prev].seq, frag_index_prev,
this_fragmentation->fragment[frag_index_prev].flags);
this_fragmentation->fragment[frag_index_prev].length = 0;
this_fragmentation->fragment[frag_index_prev].flags = 0;
if (end_frame && (!begin_frame)) return; // assembling frame failed
}
}
find_frame:
begin_index = this_fragmentation->start_index;
uint32_t b_seq = this_fragmentation->start_seq;
// Try to find a Begin sequence from the start_seq sequence to M sequence
while (b_seq < Mmin)
{
if (this_fragmentation->fragment[begin_index].length)
{
if (b_seq == this_fragmentation->fragment[begin_index].seq)
{
if (this_fragmentation->fragment[begin_index].flags & MP_BEGIN)
{
int isfoundE = 0;
// Adjust the new start sequence and start index
this_fragmentation->start_index = begin_index;
this_fragmentation->start_seq = b_seq;
// Begin Sequence found, now try to found the End Sequence to complete the frame
end_index = begin_index;
while (b_seq < Mmin)
{
if (this_fragmentation->fragment[end_index].length)
{
if (b_seq == this_fragmentation->fragment[end_index].seq)
{
if (this_fragmentation->fragment[end_index].flags & MP_END)
{
// The End sequence was found and the frame is complete
isfoundE = 1;
break;
}
}
else
{
// This fragment is lost, it was never completed the packet.
LOG(3, this_fragmentation->fragment[end_index].sid, this_fragmentation->fragment[end_index].tid,
"MPPP: (FIND END) seq_num:%d frag_index:%d flags:%02X is LOST\n",
this_fragmentation->fragment[end_index].seq, begin_index,
this_fragmentation->fragment[end_index].flags);
// this frag is lost
this_fragmentation->fragment[end_index].length = 0;
this_fragmentation->fragment[end_index].flags = 0;
// This frame is not complete find the next Begin
break;
}
}
else
{
// This frame is not complete find the next Begin if exist
break;
}
end_index = (end_index +1) & MAXFRAGNUM_MASK;
b_seq++;
}
if (isfoundE)
// The End sequence was found and the frame is complete
break;
else
// find the next Begin
begin_index = end_index;
}
}
else
{
// This fragment is lost, it was never completed the packet.
LOG(3, this_fragmentation->fragment[begin_index].sid, this_fragmentation->fragment[begin_index].tid,
"MPPP: (FIND BEGIN) seq_num:%d frag_index:%d flags:%02X is LOST\n",
this_fragmentation->fragment[begin_index].seq, begin_index,
this_fragmentation->fragment[begin_index].flags);
// this frag is lost
this_fragmentation->fragment[begin_index].length = 0;
this_fragmentation->fragment[begin_index].flags = 0;
}
}
begin_index = (begin_index +1) & MAXFRAGNUM_MASK;
b_seq++;
}
assembling_frame:
// try to assemble the frame that has the received fragment as a member
// get the beginning of this frame
begin_index = end_index = this_fragmentation->start_index;
if (this_fragmentation->fragment[begin_index].length)
{
if (!(this_fragmentation->fragment[begin_index].flags & MP_BEGIN))
{
LOG(3, this_fragmentation->fragment[begin_index].sid, this_fragmentation->fragment[begin_index].tid,
"MPPP: (NOT BEGIN) seq_num:%d frag_index:%d flags:%02X\n",
this_fragmentation->fragment[begin_index].seq, begin_index,
this_fragmentation->fragment[begin_index].flags);
// should occur only after an "M_Offset out of range"
// The start sequence must be a begin sequence
this_fragmentation->start_index = (begin_index +1) & MAXFRAGNUM_MASK;
this_fragmentation->start_seq++;
return; // assembling frame failed
}
}
else
return; // assembling frame failed
// get the end of his frame
while (this_fragmentation->fragment[end_index].length)
{
if (this_fragmentation->fragment[end_index].flags & MP_END)
break;
end_index = (end_index +1) & MAXFRAGNUM_MASK;
if (end_index == this_fragmentation->start_index)
return; // assembling frame failed
}
// return if a lost fragment is found
if (!(this_fragmentation->fragment[end_index].length))
return; // assembling frame failed
// assemble the packet
//assemble frame, process it, reset fragmentation
uint16_t cur_len = 4; // This is set to 4 to leave 4 bytes for function processipin
LOG(4, s, t, "MPPP: processing fragments from %d to %d\n", begin_index, end_index);
// Push to the receive buffer
for (i = begin_index;; i = (i + 1) & MAXFRAGNUM_MASK)
{
this_frag = &this_fragmentation->fragment[i];
if(cur_len + this_frag->length > MAXETHER)
{
LOG(2, s, t, "MPPP: discarding reassembled frames larger than MAXETHER\n");
break;
}
memcpy(this_fragmentation->reassembled_frame+cur_len, this_frag->data, this_frag->length);
LOG(5, s, t, "MPPP: processing frame at %d, with len %d\n", i, this_frag->length);
cur_len += this_frag->length;
if (i == end_index)
{
this_fragmentation->re_frame_len = cur_len;
this_fragmentation->re_frame_begin_index = begin_index;
this_fragmentation->re_frame_end_index = end_index;
// Process the resassembled frame
LOG(5, s, t, "MPPP: Process the reassembled frame, len=%d\n",cur_len);
processmpframe(s, t, this_fragmentation->reassembled_frame, this_fragmentation->re_frame_len, 1);
break;
}
}
// Set reassembled frame length to zero after processing it
this_fragmentation->re_frame_len = 0;
for (i = begin_index;; i = (i + 1) & MAXFRAGNUM_MASK)
{
this_fragmentation->fragment[i].length = 0; // Indicates that this fragment has been consumed
this_fragmentation->fragment[i].flags = 0;
if (i == end_index)
break;
}
// Set the new start_index and start_seq
this_fragmentation->start_index = (end_index + 1) & MAXFRAGNUM_MASK;
this_fragmentation->start_seq = this_fragmentation->fragment[end_index].seq + 1;
LOG(4, s, t, "MPPP after assembling: start index is = %d, start seq=%d\n", this_fragmentation->start_index, this_fragmentation->start_seq);
begin_index = this_fragmentation->start_index;
if ((this_fragmentation->fragment[begin_index].length) &&
(this_fragmentation->fragment[begin_index].seq != this_fragmentation->start_seq))
{
LOG(3, this_fragmentation->fragment[begin_index].sid, this_fragmentation->fragment[begin_index].tid,
"MPPP: (START) seq_num:%d frag_index:%d flags:%02X is LOST\n",
this_fragmentation->fragment[begin_index].seq, begin_index,
this_fragmentation->fragment[begin_index].flags);
this_fragmentation->fragment[begin_index].length = 0;
this_fragmentation->fragment[begin_index].flags = 0;
}
if (this_fragmentation->start_seq <= Mmin)
// It's possible to find other complete frame or lost frame.
goto find_frame;
else if ((this_fragmentation->fragment[begin_index].length) &&
(this_fragmentation->fragment[begin_index].flags & MP_BEGIN))
// may be that the next frame is completed
goto assembling_frame;
return;
}
// process IPv6 packet received
//
// This MUST be called with at least 4 byte behind 'p'.
// (i.e. this routine writes to p[-4]).
void processipv6in(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
{
struct in6_addr ip;
in_addr_t ipv4;
CSTAT(processipv6in);
LOG_HEX(5, "IPv6", p, l);
ip = *(struct in6_addr *) (p + 8);
ipv4 = ntohl(*(uint32_t *)(p + 16));
if (l > MAXETHER)
{
LOG(1, s, t, "IP packet too long %d\n", l);
STAT(tunnel_rx_errors);
return ;
}
if (session[s].ppp.phase != Network || session[s].ppp.ipv6cp != Opened)
return;
// no spoof
if ((ipv4 != session[s].ip || memcmp(&config->ipv6_prefix, &ip, 8)) && sessionbyipv6(ip) != s)
{
char str[INET6_ADDRSTRLEN];
LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
return;
}
// Check if it's a Router Solicition message.
if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
*(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
*(uint32_t *)(p + 34) == 0 &&
*(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
LOG(3, s, t, "Got IPv6 RS\n");
send_ipv6_ra(s, t, &ip);
return;
}
// Add on the tun header
p -= 4;
*(uint32_t *) p = htonl(PKTIPV6);
l += 4;
// Are we throttled and a slave?
if (session[s].tbf_in && !config->cluster_iam_master) {
// Pass it to the master for handling.
master_throttle_packet(session[s].tbf_in, p, l);
return;
}
// Are we throttled and a master??
if (session[s].tbf_in && config->cluster_iam_master) {
// Actually handle the throttled packets.
tbf_queue_packet(session[s].tbf_in, p, l);
return;
}
// send to ethernet
if (tun_write(p, l) < 0)
{
STAT(tun_tx_errors);
LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
l, strerror(errno), tunfd, p);
return;
}
p += 4;
l -= 4;
if (session[s].snoop_ip && session[s].snoop_port)
{
// Snooping this session
snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
}
update_sessions_in_stat(s, l);
eth_tx += l;
STAT(tun_tx_packets);
INC_STAT(tun_tx_bytes, l);
}
//
// Helper routine for the TBF filters.
// Used to send queued data in from the user.
//
void send_ipin(sessionidt s, uint8_t *buf, int len)
{
LOG_HEX(5, "IP in throttled", buf, len);
if (write(tunfd, buf, len) < 0)
{
STAT(tun_tx_errors);
LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
len, strerror(errno), tunfd, buf);
return;
}
buf += 4;
len -= 4;
if (session[s].snoop_ip && session[s].snoop_port)
{
// Snooping this session
snoop_send_packet(buf, len, session[s].snoop_ip, session[s].snoop_port);
}
// Increment packet counters
increment_counter(&session[s].cin, &session[s].cin_wrap, len);
session[s].cin_delta += len;
session[s].pin++;
sess_local[s].cin += len;
sess_local[s].pin++;
eth_tx += len;
STAT(tun_tx_packets);
INC_STAT(tun_tx_bytes, len - 4);
}
// Process CCP messages
void processccp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
{
uint8_t b[MAXETHER];
uint8_t *q;
CSTAT(processccp);
LOG_HEX(5, "CCP", p, l);
if (session[s].ppp.phase < Network)
{
LOG(2, s, t, "CCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
return;
}
if (l < 1)
{
LOG(1, s, t, "Short CCP packet\n");
STAT(tunnel_rx_errors);
}
LOG(4, s, t, "CCP: recv %s\n", ppp_code(*p));
if (*p == ConfigAck)
{
switch (session[s].ppp.ccp)
{
case RequestSent:
initialise_restart_count(s, ccp);
change_state(s, ccp, AckReceived);
break;
case AckReceived:
case Opened:
LOG(2, s, t, "CCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ccp));
sendccp(s, t);
change_state(s, ccp, RequestSent);
break;
case AckSent:
LOG(3, s, t, "CCP: Opened\n");
change_state(s, ccp, Opened);
break;
default:
LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
}
}
else if (*p == ConfigReq)
{
if (l < 6) // accept no compression
*p = ConfigAck;
else // compression requested--reject
*p = ConfigRej;
q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP, 0, 0, 0);
if (!q) return;
switch (session[s].ppp.ccp)
{
case Closed:
q = makeppp(b, sizeof(b), p, 2, s, t, PPPCCP, 0, 0, 0);
if (!q) return;
*q = TerminateAck;
*((uint16_t *) (q + 2)) = htons(l = 4);
break;
case Stopped:
initialise_restart_count(s, ccp);
sendccp(s, t);
if (*q == ConfigAck)
change_state(s, ccp, AckSent);
else
change_state(s, ccp, RequestSent);
break;
case RequestSent:
if (*q == ConfigAck)
change_state(s, ccp, AckSent);
break;
case AckReceived:
if (*q == ConfigAck)
change_state(s, ccp, Opened);
break;
case Opened:
initialise_restart_count(s, ccp);
sendccp(s, t);
/* fallthrough */
case AckSent:
if (*q == ConfigAck)
change_state(s, ccp, AckSent);
else
change_state(s, ccp, RequestSent);
break;
default:
LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
return;
}
LOG(4, s, t, "CCP: send %s\n", ppp_code(*q));
tunnelsend(b, l + (q - b), t);
}
else if (*p == TerminateReq)
{
*p = TerminateAck;
q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP, 0, 0, 0);
if (!q) return;
LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
tunnelsend(b, l + (q - b), t);
change_state(s, ccp, Stopped);
}
else if (*p != CodeRej)
{
ppp_code_rej(s, t, PPPCCP, "CCP", p, l, b, sizeof(b));
}
}
// send a CHAP challenge
void sendchap(sessionidt s, tunnelidt t)
{
uint8_t b[MAXETHER];
uint16_t r;
uint8_t *q;
CSTAT(sendchap);
r = radiusnew(s);
if (!r)
{
LOG(1, s, t, "No RADIUS to send challenge\n");
STAT(tunnel_tx_errors);
return;
}
LOG(1, s, t, "Send CHAP challenge\n");
radius[r].chap = 1; // CHAP not PAP
radius[r].id++;
if (radius[r].state != RADIUSCHAP)
radius[r].try = 0;
radius[r].state = RADIUSCHAP;
radius[r].retry = backoff(radius[r].try++);
if (radius[r].try > 5)
{
sessionshutdown(s, "CHAP timeout.", CDN_ADMIN_DISC, TERM_REAUTHENTICATION_FAILURE);
STAT(tunnel_tx_errors);
return ;
}
q = makeppp(b, sizeof(b), 0, 0, s, t, PPPCHAP, 0, 0, 0);
if (!q) return;
*q = 1; // challenge
q[1] = radius[r].id; // ID
q[4] = 16; // value size (size of challenge)
memcpy(q + 5, radius[r].auth, 16); // challenge
strcpy((char *) q + 21, hostname); // our name
*(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
}
// fill in a L2TP message with a PPP frame,
// returns start of PPP frame
uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype, uint8_t prio, bundleidt bid, uint8_t mp_bits)
{
uint16_t hdr = 0x0002; // L2TP with no options
uint16_t type = mtype;
uint8_t *start = b;
if (t == TUNNEL_ID_PPPOE)
{
return pppoe_makeppp(b, size, p, l, s, t, mtype, prio, bid, mp_bits);
}
if (size < 16) // Need more space than this!!
{
LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
return NULL;
}
if (prio) hdr |= 0x0100; // set priority bit
*(uint16_t *) (b + 0) = htons(hdr);
*(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
*(uint16_t *) (b + 4) = htons(session[s].far); // session
b += 6;
// Check whether this session is part of multilink
if (bid)
{
if (bundle[bid].num_of_links > 1)
type = PPPMP; // Change PPP message type to the PPPMP
else
bid = 0;
}
if (type == PPPLCP || !(session[s].flags & SESSION_ACFC))
{
*(uint16_t *) b = htons(0xFF03); // HDLC header
b += 2;
}
if (type < 0x100 && session[s].flags & SESSION_PFC)
{
*b++ = type;
}
else
{
*(uint16_t *) b = htons(type);
b += 2;
}
if (bid)
{
// Set the sequence number and (B)egin (E)nd flags
if (session[s].mssf)
{
// Set the multilink bits
uint16_t bits_send = mp_bits;
*(uint16_t *) b = htons((bundle[bid].seq_num_t & 0x0FFF)|bits_send);
b += 2;
}
else
{
*(uint32_t *) b = htonl(bundle[bid].seq_num_t);
// Set the multilink bits
*b = mp_bits;
b += 4;
}
bundle[bid].seq_num_t++;
// Add the message type if this fragment has the begin bit set
if (mp_bits & MP_BEGIN)
{
//*b++ = mtype; // The next two lines are instead of this
*(uint16_t *) b = htons(mtype); // Message type
b += 2;
}
}
if ((b - start) + l > size)
{
LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%td)\n", size, (b - start) + l);
return NULL;
}
// Copy the payload
if (p && l)
memcpy(b, p, l);
return b;
}
// fill in a L2TP message with a PPP frame,
// returns start of PPP frame
//(note: THIS ROUTINE CAN WRITES TO p[-28]).
uint8_t *opt_makeppp(uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype, uint8_t prio, bundleidt bid, uint8_t mp_bits)
{
uint16_t hdr = 0x0002; // L2TP with no options
uint16_t type = mtype;
uint8_t *b = p;
if (t == TUNNEL_ID_PPPOE)
{
return opt_pppoe_makeppp(p, l, s, t, mtype, prio, bid, mp_bits);
}
// Check whether this session is part of multilink
if (bid)
{
if (bundle[bid].num_of_links > 1)
type = PPPMP; // Change PPP message type to the PPPMP
else
bid = 0;
}
if (bid)
{
// Add the message type if this fragment has the begin bit set
if (mp_bits & MP_BEGIN)
{
b -= 2;
*(uint16_t *) b = htons(mtype); // Message type
}
// Set the sequence number and (B)egin (E)nd flags
if (session[s].mssf)
{
// Set the multilink bits
uint16_t bits_send = mp_bits;
b -= 2;
*(uint16_t *) b = htons((bundle[bid].seq_num_t & 0x0FFF)|bits_send);
}
else
{
b -= 4;
*(uint32_t *) b = htonl(bundle[bid].seq_num_t);
// Set the multilink bits
*b = mp_bits;
}
bundle[bid].seq_num_t++;
}
if (type < 0x100 && session[s].flags & SESSION_PFC)
{
b--;
*b = type;
}
else
{
b -= 2;
*(uint16_t *) b = htons(type);
}
if (type == PPPLCP || !(session[s].flags & SESSION_ACFC))
{
b -= 2;
*(uint16_t *) b = htons(0xFF03); // HDLC header
}
if (prio) hdr |= 0x0100; // set priority bit
b -= 2;
*(uint16_t *) b = htons(session[s].far); // session
b -= 2;
*(uint16_t *) b = htons(tunnel[t].far); // tunnel
b -= 2;
*(uint16_t *) b = htons(hdr);
return b;
}
static int add_lcp_auth(uint8_t *b, int size, int authtype)
{
int len = 0;
if ((authtype == AUTHCHAP && size < 5) || size < 4)
return 0;
*b++ = 3; // Authentication-Protocol
if (authtype == AUTHCHAP)
{
len = *b++ = 5; // length
*(uint16_t *) b = htons(PPPCHAP); b += 2;
*b++ = 5; // MD5
}
else if (authtype == AUTHPAP)
{
len = *b++ = 4; // length
*(uint16_t *) b = htons(PPPPAP); b += 2;
}
else
{
LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype);
}
return len;
}
// Send LCP ConfigReq for MRU, authentication type and magic no
void sendlcp(sessionidt s, tunnelidt t)
{
uint8_t b[500], *q, *l;
int authtype = sess_local[s].lcp_authtype;
if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPLCP, 0, 0, 0)))
return;
LOG(3, s, t, "LCP: send ConfigReq%s%s%s including MP options\n",
authtype ? " (" : "",
authtype ? (authtype == AUTHCHAP ? "CHAP" : "PAP") : "",
authtype ? ")" : "");
l = q;
*l++ = ConfigReq;
*l++ = ++sess_local[s].lcp_ident; // ID
l += 2; //Save space for length
if (sess_local[s].ppp_mru)
{
*l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
*(uint16_t *) l = htons(sess_local[s].ppp_mru); l += 2;
}
if (authtype)
l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
if (session[s].magic)
{
*l++ = 5; *l++ = 6; // Magic-Number (length 6)
*(uint32_t *) l = htonl(session[s].magic);
l += 4;
}
if (sess_local[s].mp_mrru)
{
*l++ = 17; *l++ = 4; // Multilink Max-Receive-Reconstructed-Unit (length 4)
*(uint16_t *) l = htons(sess_local[s].mp_mrru); l += 2;
}
if (sess_local[s].mp_epdis)
{
*l++ = 19; *l++ = 7; // Multilink Endpoint Discriminator (length 7)
*l++ = IPADDR; // Endpoint Discriminator class
*(uint32_t *) l = htonl(sess_local[s].mp_epdis);
l += 4;
}
*(uint16_t *)(q + 2) = htons(l - q); // Length
LOG_HEX(5, "PPPLCP", q, l - q);
if (config->debug > 3) dumplcp(q, l - q);
tunnelsend(b, (l - b), t);
restart_timer(s, lcp);
}
// Send CCP request for no compression
void sendccp(sessionidt s, tunnelidt t)
{
uint8_t b[500], *q;
if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPCCP, 0, 0, 0)))
return;
LOG(3, s, t, "CCP: send ConfigReq (no compression)\n");
*q = ConfigReq;
*(q + 1) = ++sess_local[s].lcp_ident; // ID
*(uint16_t *)(q + 2) = htons(4); // Length
LOG_HEX(5, "PPPCCP", q, 4);
tunnelsend(b, (q - b) + 4 , t);
restart_timer(s, ccp);
}
// Reject unknown/unconfigured protocols
void protoreject(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l, uint16_t proto)
{
uint8_t buf[MAXETHER];
uint8_t *q;
int mru = session[s].mru;
if (mru < MINMTU) mru = MINMTU;
if (mru > sizeof(buf)) mru = sizeof(buf);
l += 6;
if (l > mru) l = mru;
q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPLCP, 0, 0, 0);
if (!q) return;
*q = ProtocolRej;
*(q + 1) = ++sess_local[s].lcp_ident;
*(uint16_t *)(q + 2) = htons(l);
*(uint16_t *)(q + 4) = htons(proto);
memcpy(q + 6, p, l - 6);
if (proto == PPPIPV6CP)
LOG(3, s, t, "LCP: send ProtocolRej (IPV6CP: not configured)\n");
else
LOG(2, s, t, "LCP: sent ProtocolRej (0x%04X: unsupported)\n", proto);
tunnelsend(buf, l + (q - buf), t);
}
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