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l2tpns/ppp.c
bodea 98b15d3dd0 configure MRU in initlcp
2005-05-07 11:57:53 +00:00

1257 lines
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// L2TPNS PPP Stuff
char const *cvs_id_ppp = "$Id: ppp.c,v 1.51 2005/05/07 11:57:53 bodea Exp $";
#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"
extern tunnelt *tunnel;
extern sessiont *session;
extern radiust *radius;
extern int tunfd;
extern char hostname[];
extern uint32_t eth_tx;
extern time_t time_now;
extern configt *config;
static void initccp(tunnelidt t, sessionidt s);
// Process PAP messages
void processpap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
{
char user[MAXUSER];
char pass[MAXPASS];
uint16_t hl;
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.", 3, 0);
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.", 3, 0);
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.", 3, 0);
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);
}
if (session[s].ip || !sess_local[s].radius)
{
// respond now, either no RADIUS available or already authenticated
uint8_t b[MAXCONTROL];
uint8_t id = p[1];
uint8_t *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
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
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);
session[s].flags &= ~SF_IPCP_ACKED;
}
else
{
LOG(1, s, t, "No radius session available to authenticate session...\n");
}
LOG(3, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK");
tunnelsend(b, 5 + (p - b), t); // send it
sessionshutdown(s, "PAP authentication failed.", 3, 0);
}
else
{
// set up RADIUS request
uint16_t r = sess_local[s].radius;
// 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);
radiussend(r, RADIUSAUTH);
}
}
// Process CHAP messages
void processchap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
{
uint16_t r;
uint16_t hl;
CSTAT(processchap);
LOG_HEX(5, "CHAP", p, l);
r = sess_local[s].radius;
if (!r)
{
LOG(1, s, t, "Unexpected CHAP message\n");
STAT(tunnel_rx_errors);
return;
}
if (l < 4)
{
LOG(1, s, t, "Short CHAP %u bytes\n", l);
STAT(tunnel_rx_errors);
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);
return ;
}
l = hl;
if (*p != 2)
{
LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
STAT(tunnel_rx_errors);
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);
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);
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);
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);
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);
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_lcp_type((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", lcp_type(type), ntohs(*(uint16_t *)(o + 2)));
else
LOG(4, 0, 0, " %s odd length %d\n", lcp_type(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", lcp_type(type), asyncmap);
}
else
LOG(4, 0, 0, " %s odd length %d\n", lcp_type(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", lcp_type(type), proto,
proto == PPPPAP ? "PAP" : "UNSUPPORTED");
}
else if (length == 5)
{
int proto = ntohs(*(uint16_t *)(o + 2));
int algo = *(uint8_t *)(o + 4);
LOG(4, 0, 0, " %s 0x%x 0x%x (%s)\n", lcp_type(type), proto, algo,
(proto == PPPCHAP && algo == 5) ? "CHAP MD5" : "UNSUPPORTED");
}
else
LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length);
break;
case 4: // Quality-Protocol
{
uint32_t qp = ntohl(*(uint32_t *)(o + 2));
LOG(4, 0, 0, " %s %x\n", lcp_type(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", lcp_type(type), magicno);
}
else
LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length);
break;
case 7: // Protocol-Field-Compression
case 8: // Address-And-Control-Field-Compression
LOG(4, 0, 0, " %s\n", lcp_type(type));
break;
default:
LOG(2, 0, 0, " Unknown PPP LCP Option type %d\n", type);
break;
}
x -= length;
o += length;
}
}
// Process LCP messages
void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
{
uint8_t b[MAXCONTROL];
uint8_t *q = NULL;
uint32_t magicno = 0;
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 (*p == ConfigAck)
{
LOG(3, s, t, "LCP: Discarding ConfigAck\n");
session[s].flags |= SF_LCP_ACKED;
}
else if (*p == ConfigReq)
{
int x = l - 4;
uint8_t *o = (p + 4);
uint8_t *response = 0;
LOG(3, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
if (config->debug > 3) dumplcp(p, l);
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
session[s].mru = ntohs(*(uint16_t *)(o + 2));
break;
case 2: // Async-Control-Character-Map
if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
break;
if (response && *response != ConfigNak) // rej already queued
break;
LOG(2, s, t, " Remote requesting asyncmap. Rejecting.\n");
if (!response)
{
q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
if (!q) break;
*q = ConfigNak;
q += 4;
}
if ((q - b + 11) > sizeof(b))
{
LOG(2, s, t, "LCP overflow for asyncmap ConfigNak.\n");
break;
}
*q++ = type;
*q++ = 6;
memset(q, 0, 4); // asyncmap 0
q += 4;
*((uint16_t *) (response + 2)) = htons(q - response); // LCP header length
break;
case 3: // Authentication-Protocol
{
int proto = ntohs(*(uint16_t *)(o + 2));
char proto_name[] = "0x0000";
if (proto == PPPPAP)
{
if (config->radius_authtypes & AUTHPAP)
break;
strcpy(proto_name, "PAP");
}
else if (proto == PPPCHAP)
{
if (config->radius_authtypes & AUTHCHAP
&& *(o + 4) == 5) // MD5
break;
strcpy(proto_name, "CHAP");
}
else
sprintf(proto_name, "%#4.4x", proto);
if (response && *response != ConfigNak) // rej already queued
break;
LOG(2, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name);
if (!response)
{
q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
if (!q) break;
*q = ConfigNak;
q += 4;
}
if ((q - b + 5) > sizeof(b)) // 5 is the larger (CHAP+MD5) of the two NAKs
{
LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name);
break;
}
*q++ = type;
if (config->radius_authprefer == AUTHCHAP)
{
*q++ = 5;
*(uint16_t *) q = htons(PPPCHAP); q += 2;
*q++ = 5; // MD5
}
else
{
*q++ = 4;
*(uint16_t *) q = htons(PPPPAP); q += 2;
}
*((uint16_t *) (response + 2)) = htons(q - response); // LCP header length
break;
}
break;
case 5: // Magic-Number
magicno = ntohl(*(uint32_t *)(o + 2));
break;
case 4: // Quality-Protocol
case 7: // Protocol-Field-Compression
case 8: // Address-And-Control-Field-Compression
break;
default: // Reject any unknown options
LOG(2, s, t, " Rejecting PPP LCP Option type %d\n", type);
if (!response || *response != ConfigRej) // drop nak in favour of rej
{
q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
if (!q) break;
*q = ConfigRej;
q += 4;
}
if ((q - b + length) > sizeof(b))
{
LOG(2, s, t, "LCP overflow for ConfigRej (type=%d).\n", type);
break;
}
memcpy(q, o, length);
q += length;
*((uint16_t *) (response + 2)) = htons(q - response); // LCP header length
}
x -= length;
o += length;
}
if (!response)
{
// Send back a ConfigAck
q = response = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
if (!q) return;
*q = ConfigAck;
}
LOG(3, s, t, "Sending %s\n", ppp_lcp_type(*response));
tunnelsend(b, l + (q - b), t);
if (!(session[s].flags & SF_LCP_ACKED))
initlcp(t, s);
}
else if (*p == ConfigNak)
{
LOG(1, s, t, "Remote end sent a ConfigNak. Ignoring\n");
if (config->debug > 3) dumplcp(p, l);
return;
}
else if (*p == TerminateReq)
{
LOG(3, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
*p = TerminateAck; // close
q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
if (!q) return;
tunnelsend(b, l + (q - b), t); // send it
sessionshutdown(s, "Remote end closed connection.", 3, 0);
}
else if (*p == TerminateAck)
{
sessionshutdown(s, "Connection closed.", 3, 0);
}
else if (*p == ProtocolRej)
{
if (*(uint16_t *) (p+4) == htons(PPPIPV6CP))
{
LOG(3, s, t, "IPv6 rejected\n");
session[s].flags |= SF_IPV6_NACKED;
}
else
{
LOG(1, s, t, "Unexpected LCP protocol reject 0x%X\n",
ntohs(*(uint16_t *) (p+4)));
STAT(tunnel_rx_errors);
}
}
else if (*p == EchoReq)
{
LOG(5, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
*p = EchoReply; // reply
*(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
if (!q) return;
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 == IdentRequest)
{
*p = CodeRej;
if (l > MAXCONTROL)
{
LOG(1, s, t, "Truncated Ident Packet (length=%d) to 1400 bytes\n", l);
l = 1400;
}
q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
if (!q) return;
LOG_HEX(5, "LCPIdentRej", q, l + 4);
tunnelsend(b, 12 + 4 + l, t);
}
else
{
LOG(1, s, t, "Unexpected LCP code %d\n", *p);
STAT(tunnel_rx_errors);
return ;
}
}
// find a PPP option, returns point to option, or 0 if not found
static uint8_t *findppp(uint8_t *b, uint8_t mtype)
{
uint16_t l = ntohs(*(uint16_t *) (b + 2));
if (l < 4)
return 0;
b += 4;
l -= 4;
while (l)
{
if (l < b[1] || !b[1])
return 0; // faulty
if (*b == mtype)
return b;
l -= b[1];
b += b[1];
}
return 0;
}
// Process IPCP messages
void processipcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
{
uint16_t hl;
CSTAT(processipcp);
LOG_HEX(5, "IPCP", p, l);
if (l < 5)
{
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 (*p == ConfigAck)
{
// happy with our IPCP
uint16_t r = sess_local[s].radius;
if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden)
{
if (!r)
r = radiusnew(s);
if (r)
radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last
}
session[s].flags |= SF_IPCP_ACKED;
LOG(3, s, t, "IPCP Acked, session is now active\n");
// clear LCP_ACKED/CCP_ACKED flag for possible fast renegotiaion for routers
session[s].flags &= ~(SF_LCP_ACKED|SF_CCP_ACKED);
return;
}
if (*p != ConfigReq)
{
LOG(1, s, t, "Unexpected IPCP code %d\n", *p);
STAT(tunnel_rx_errors);
return ;
}
LOG(4, s, t, "IPCP ConfigReq received\n");
if (!session[s].ip)
{
LOG(3, s, t, "Waiting on radius reply\n");
return; // have to wait on RADIUS reply
}
// form a config reply quoting the IP in the session
{
uint8_t b[MAXCONTROL];
uint8_t *i, *q;
q = p + 4;
i = p + l;
while (q < i && q[1])
{
if (*q != 0x81 && *q != 0x83 && *q != 3)
break;
q += q[1];
}
if (q < i)
{
// reject
uint16_t n = 4;
i = p + l;
if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
return;
*q = ConfigRej;
p += 4;
while (p < i && p[1])
{
if (*p != 0x81 && *p != 0x83 && *p != 3)
{
LOG(2, s, t, "IPCP reject %d\n", *p);
memcpy(q + n, p, p[1]);
n += p[1];
}
p += p[1];
}
*(uint16_t *) (q + 2) = htons(n);
LOG(4, s, t, "Sending ConfigRej\n");
tunnelsend(b, n + (q - b), t); // send it
}
else
{
LOG(4, s, t, "Sending ConfigAck\n");
*p = ConfigAck;
if ((i = findppp(p, 0x81))) // Primary DNS address
{
if (*(uint32_t *) (i + 2) != htonl(session[s].dns1))
{
*(uint32_t *) (i + 2) = htonl(session[s].dns1);
*p = ConfigNak;
LOG(5, s, t, " DNS1 = %s\n",
fmtaddr(htonl(session[s].dns1), 0));
}
}
if ((i = findppp(p, 0x83))) // Secondary DNS address (TBA, is it)
{
if (*(uint32_t *) (i + 2) != htonl(session[s].dns2))
{
*(uint32_t *) (i + 2) = htonl(session[s].dns2);
*p = ConfigNak;
LOG(5, s, t, " DNS2 = %s\n",
fmtaddr(htonl(session[s].dns2), 0));
}
}
i = findppp(p, 3); // IP address
if (!i || i[1] != 6)
{
LOG(1, s, t, "No IP in IPCP request\n");
STAT(tunnel_rx_errors);
return ;
}
if (*(uint32_t *) (i + 2) != htonl(session[s].ip))
{
*(uint32_t *) (i + 2) = htonl(session[s].ip);
*p = ConfigNak;
LOG(4, s, t, " No, a ConfigNak, client is requesting IP - sending %s\n",
fmtaddr(htonl(session[s].ip), 0));
}
if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
return;
tunnelsend(b, l + (q - b), t); // send it
}
}
}
// Process IPV6CP messages
void processipv6cp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
{
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 (*p == ConfigAck)
{
// happy with our IPV6CP
session[s].flags |= SF_IPV6CP_ACKED;
LOG(3, s, t, "IPV6CP Acked, IPv6 is now active\n");
// Add a routed block if configured.
if (session[s].ipv6prefixlen)
{
route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
session[s].flags |= SF_IPV6_ROUTED;
}
// Send an initial RA (TODO: Should we send these regularly?)
send_ipv6_ra(t, s, NULL);
return;
}
if (*p != ConfigReq)
{
LOG(1, s, t, "Unexpected IPV6CP code %d\n", *p);
STAT(tunnel_rx_errors);
return;
}
LOG(4, s, t, "IPV6CP ConfigReq received\n");
if (ntohs(*(uint16_t *) (p + 2)) > l)
{
LOG(1, s, t, "Length mismatch IPV6CP %d/%d\n", ntohs(*(uint16_t *) (p + 2)), l);
STAT(tunnel_rx_errors);
return ;
}
if (!session[s].ip)
{
LOG(3, s, t, "Waiting on radius reply\n");
return; // have to wait on RADIUS reply
}
// form a config reply quoting the IP in the session
{
uint8_t b[MAXCONTROL];
uint8_t *i,
*q;
l = ntohs(*(uint16_t *) (p + 2)); // We must use length from IPV6CP len field
q = p + 4;
i = p + l;
while (q < i && q[1])
{
if (*q != 1)
break;
q += q[1];
}
if (q < i)
{
// reject
uint16_t n = 4;
i = p + l;
if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPV6CP)))
{
LOG(2, s, t, "Failed to send IPV6CP ConfigRej\n");
return;
}
*q = ConfigRej;
p += 4;
while (p < i && p[1])
{
if (*p != 1)
{
LOG(2, s, t, "IPV6CP reject %d\n", *p);
memcpy(q + n, p, p[1]);
n += p[1];
}
p += p[1];
}
*(uint16_t *) (q + 2) = htons(n);
LOG(4, s, t, "Sending ConfigRej\n");
tunnelsend(b, n + (q - b), t); // send it
}
else
{
LOG(4, s, t, "Sending ConfigAck\n");
*p = ConfigAck;
i = findppp(p, 1); // IP address
if (!i || i[1] != 10)
{
LOG(1, s, t, "No IP in IPV6CP request\n");
STAT(tunnel_rx_errors);
return ;
}
if ((*(uint32_t *) (i + 2) != htonl(session[s].ip)) ||
(*(uint32_t *) (i + 6) != 0))
{
*(uint32_t *) (i + 2) = htonl(session[s].ip);
*(uint32_t *) (i + 6) = 0;
*p = ConfigNak;
LOG(4, s, t,
" No, a ConfigNak, client is "
"requesting IP - sending %s\n",
fmtaddr(htonl(session[s].ip), 0));
}
if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPV6CP)))
{
LOG(2, s, t, " Failed to send IPV6CP packet.\n");
return;
}
tunnelsend(b, l + (q - b), t); // send it
}
}
}
// 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(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
{
in_addr_t ip;
CSTAT(processipin);
LOG_HEX(5, "IP", p, l);
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 ;
}
// no spoof (do sessionbyip to handled statically routed subnets)
if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
{
LOG(5, 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;
// Add on the tun header
p -= 4;
*(uint32_t *) p = htonl(PKTIP);
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;
}
if (session[s].snoop_ip && session[s].snoop_port)
{
// Snooping this session
snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
}
session[s].cin += l - 4;
session[s].total_cin += l - 4;
sess_local[s].cin += l - 4;
session[s].pin++;
eth_tx += l - 4;
STAT(tun_tx_packets);
INC_STAT(tun_tx_bytes, l - 4);
}
// 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(tunnelidt t, sessionidt s, 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 ;
}
// 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(t, s, &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;
}
if (session[s].snoop_ip && session[s].snoop_port)
{
// Snooping this session
snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
}
session[s].cin += l - 4;
session[s].total_cin += l - 4;
sess_local[s].cin += l - 4;
session[s].pin++;
eth_tx += l - 4;
STAT(tun_tx_packets);
INC_STAT(tun_tx_bytes, l - 4);
}
//
// 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;
}
if (session[s].snoop_ip && session[s].snoop_port)
{
// Snooping this session
snoop_send_packet(buf + 4, len - 4, session[s].snoop_ip, session[s].snoop_port);
}
// Increment packet counters
session[s].cin += len - 4;
session[s].total_cin += len - 4;
sess_local[s].cin += len - 4;
session[s].pin++;
eth_tx += len - 4;
STAT(tun_tx_packets);
INC_STAT(tun_tx_bytes, len - 4);
}
// Process CCP messages
void processccp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
{
uint8_t b[MAXCONTROL];
uint8_t *q;
CSTAT(processccp);
LOG_HEX(5, "CCP", p, l);
switch (l > 1 ? *p : 0)
{
case ConfigAck:
session[s].flags |= SF_CCP_ACKED;
return;
case ConfigReq:
if (l < 6) // accept no compression
{
*p = ConfigAck;
break;
}
// compression requested--reject
*p = ConfigRej;
// send CCP request for no compression for our end if not negotiated
if (!(session[s].flags & SF_CCP_ACKED))
initccp(t, s);
break;
case TerminateReq:
*p = TerminateAck;
break;
default:
if (l > 1)
LOG(1, s, t, "Unexpected CCP request code %d\n", *p);
else
LOG(1, s, t, "Short CCP packet\n");
STAT(tunnel_rx_errors);
return;
}
if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
return;
tunnelsend(b, l + (q - b), t); // send it
}
// send a CHAP challenge
void sendchap(tunnelidt t, sessionidt s)
{
uint8_t b[MAXCONTROL];
uint16_t r = sess_local[s].radius;
uint8_t *q;
CSTAT(sendchap);
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.", 3, 0);
STAT(tunnel_tx_errors);
return ;
}
q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
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(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,
// copies existing PPP message and changes magic number if seen
// returns start of PPP frame
uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, tunnelidt t, sessionidt s, uint16_t mtype)
{
if (size < 12) // Need more space than this!!
{
static int backtrace_count = 0;
LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
log_backtrace(backtrace_count, 5)
return NULL;
}
*(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options
*(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
*(uint16_t *) (b + 4) = htons(session[s].far); // session
b += 6;
if (mtype == PPPLCP || !(session[s].l2tp_flags & SESSIONACFC))
{
*(uint16_t *) b = htons(0xFF03); // HDLC header
b += 2;
}
if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
*b++ = mtype;
else
{
*(uint16_t *) b = htons(mtype);
b += 2;
}
if (l + 12 > size)
{
static int backtrace_count = 0;
LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
log_backtrace(backtrace_count, 5)
return NULL;
}
if (p && l)
memcpy(b, p, l);
return b;
}
// Send initial LCP ConfigReq for preferred authentication type, set magic no and MRU
void initlcp(tunnelidt t, sessionidt s)
{
char b[500], *q, *l;
if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP)))
return;
LOG(4, s, t, "Sending LCP ConfigReq for %s\n",
config->radius_authprefer == AUTHCHAP ? "CHAP" : "PAP");
if (!session[s].mru)
session[s].mru = DEFAULT_MRU;
l = q;
*l++ = ConfigReq;
*l++ = (time_now % 255) + 1; // ID
*l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
*(uint16_t *) l = htons(session[s].mru); l += 2;
*l++ = 3; // Authentication-Protocol
if (config->radius_authprefer == AUTHCHAP)
{
*l++ = 5; // length
*(uint16_t *) l = htons(PPPCHAP); l += 2;
*l++ = 5; // MD5
}
else
{
*l++ = 4; // length
*(uint16_t *) l = htons(PPPPAP); l += 2;
}
*l++ = 5; *l++ = 6; // Magic-Number (length 6)
*(uint32_t *) l = htonl(session[s].magic);
l += 4;
*(uint16_t *)(q + 2) = htons(l - q); // Length
LOG_HEX(5, "PPPLCP", q, l - q);
tunnelsend(b, (l - b), t);
}
// Send CCP request for no compression
static void initccp(tunnelidt t, sessionidt s)
{
char b[500], *q;
if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP)))
return;
LOG(4, s, t, "Sending CCP ConfigReq for no compression\n");
*q = ConfigReq;
*(uint8_t *)(q + 1) = (time_now % 255) + 1; // ID
*(uint16_t *)(q + 2) = htons(4); // Length
LOG_HEX(5, "PPPCCP", q, 4);
tunnelsend(b, (q - b) + 4 , t);
}
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