Initial revision
This commit is contained in:
fred_nerk
commit
3aa4eda8b1
42 changed files with 16139 additions and 0 deletions
725
ppp.c
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725
ppp.c
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// L2TPNS PPP Stuff
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// $Id: ppp.c,v 1.1 2003/12/16 07:07:39 fred_nerk Exp $
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include <stdlib.h>
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#include "l2tpns.h"
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#include "constants.h"
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#include "plugin.h"
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#include "util.h"
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extern char debug;
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extern tunnelt *tunnel;
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extern sessiont *session;
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extern radiust *radius;
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extern u16 tapmac[3];
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extern int tapfd;
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extern char hostname[1000];
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extern struct Tstats *_statistics;
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extern unsigned long eth_tx;
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extern time_t time_now;
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// Process PAP messages
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void processpap(tunnelidt t, sessionidt s, u8 * p, u16 l)
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{
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char user[129];
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char pass[129];
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#ifdef STAT_CALLS
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STAT(call_processpap);
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#endif
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log_hex(5, "PAP", p, l);
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if (l < 4)
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{
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log(1, 0, s, t, "Short PAP %u bytes", l);
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STAT(tunnel_rx_errors);
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return ;
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}
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if (*p != 1)
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{
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log(1, 0, s, t, "Unexpected PAP code %d\n", *p);
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STAT(tunnel_rx_errors);
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return ;
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}
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if (ntohs(*(u16 *) (p + 2)) > l)
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{
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log(1, 0, s, t, "Length mismatch PAP %d/%d\n", ntohs(*(u16 *) (p + 2)), l);
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STAT(tunnel_rx_errors);
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return ;
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}
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{
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u8 *b = p;
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b += 4;
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if (*b && *b < sizeof(user))
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memcpy(user, b + 1, *b);
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user[*b] = 0;
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b += 1 + *b;
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if (*b && *b < sizeof(pass))
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memcpy(pass, b + 1, *b);
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pass[*b] = 0;
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log(3, 0, s, t, "PAP login %s/%s\n", user, pass);
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}
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if (session[s].ip || !session[s].radius)
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{
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// respond now, either no RADIUS available or already authenticated
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u8 b[MAXCONTROL];
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u8 id = p[1];
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u8 *p = makeppp(b, 0, 0, t, s, PPPPAP);
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if (session[s].ip)
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*p = 2; // ACK
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else
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*p = 3; // cant authorise
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p[1] = id;
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*(u16 *) (p + 2) = htons(5); // length
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p[4] = 0; // no message
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if (session[s].ip)
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{
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log(3, session[s].ip, s, t, "%d Already an IP allocated: %s (%d)\n", getpid(), inet_toa(htonl(session[s].ip)), session[s].ip);
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}
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else
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{
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log(1, 0, s, t, "No radius session available to authenticate session...\n");
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}
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log(3, 0, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK");
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tunnelsend(b, 5 + (p - b), t); // send it
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}
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else
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{ // set up RADIUS request
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u8 r = session[s].radius;
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// Run PRE_AUTH plugins
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struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
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run_plugins(PLUGIN_PRE_AUTH, &packet);
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if (!packet.continue_auth)
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{
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log(3, 0, s, t, "A plugin rejected PRE_AUTH\n");
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if (packet.username) free(packet.username);
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if (packet.password) free(packet.password);
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return;
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}
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strncpy(session[s].user, packet.username, sizeof(session[s].user));
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strncpy(radius[r].pass, packet.password, sizeof(radius[r].pass));
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free(packet.username);
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free(packet.password);
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radius[r].id = p[1];
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log(3, 0, s, t, "Sending login for %s/%s to radius\n", user, pass);
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radiussend(r, RADIUSAUTH);
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}
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}
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// Process CHAP messages
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void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l)
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{
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u8 r;
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u16 len;
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#ifdef STAT_CALLS
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STAT(call_processchap);
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#endif
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log_hex(5, "CHAP", p, l);
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r = session[s].radius;
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if (!r)
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{
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log(1, 0, s, t, "Unexpected CHAP message\n");
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STAT(tunnel_rx_errors);
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return;
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}
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if (*p != 2)
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{
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log(1, 0, s, t, "Unexpected CHAP response code %d\n", *p);
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STAT(tunnel_rx_errors);
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return;
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}
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if (p[1] != radius[r].id)
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{
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log(1, 0, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
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STAT(tunnel_rx_errors);
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return ;
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}
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len = ntohs(*(u16 *) (p + 2));
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if (len > l)
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{
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log(1, 0, s, t, "Bad CHAP length %d\n", len);
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STAT(tunnel_rx_errors);
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return ;
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}
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if (p[4] != 16)
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{
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log(1, 0, s, t, "Bad CHAP response length %d\n", p[4]);
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STAT(tunnel_rx_errors);
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return ;
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}
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if (len - 21 >= sizeof(session[s].user))
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{
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log(1, 0, s, t, "CHAP user too long %d\n", len - 21);
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STAT(tunnel_rx_errors);
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return ;
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}
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// Run PRE_AUTH plugins
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{
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struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
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packet.username = calloc(len-20, 1);
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packet.password = calloc(16, 1);
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memcpy(packet.username, p + 21, len - 21);
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memcpy(packet.password, p + 5, 16);
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run_plugins(PLUGIN_PRE_AUTH, &packet);
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if (!packet.continue_auth)
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{
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log(3, 0, s, t, "A plugin rejected PRE_AUTH\n");
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if (packet.username) free(packet.username);
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if (packet.password) free(packet.password);
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return;
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}
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strncpy(session[s].user, packet.username, sizeof(session[s].user));
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memcpy(radius[r].pass, packet.password, 16);
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free(packet.username);
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free(packet.password);
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}
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radius[r].chap = 1;
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radiussend(r, RADIUSAUTH);
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log(3, 0, s, t, "CHAP login %s\n", session[s].user);
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}
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char *ppp_lcp_types[] = {
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NULL,
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"ConfigReq",
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"ConfigAck",
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"ConfigNak",
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"ConfigRej",
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"TerminateReq",
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"TerminateAck",
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"CodeRej",
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"ProtocolRej",
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"EchoReq",
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"EchoReply",
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"DiscardRequest",
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};
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void dumplcp(char *p, int l)
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{
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signed int x = l - 3;
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char *o = (p + 3);
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log_hex(5, "PPP LCP Packet", p, l);
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log(4, 0, 0, 0, "PPP LCP Packet type %d (%s)\n", *p, ppp_lcp_types[(int)*p]);
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log(4, 0, 0, 0, "Length: %d\n", l);
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if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
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return;
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while (x > 2)
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{
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int type = *(u8 *)(o);
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int length = *(u8 *)(o + 1);
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if (length == 0)
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{
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log(4, 0, 0, 0, " Option length is 0...\n");
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break;
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}
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if (type == 0)
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{
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log(4, 0, 0, 0, " Option type is 0...\n");
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x -= length;
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o += length;
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continue;
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}
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switch (type)
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{
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case 1: // Maximum-Receive-Unit
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log(4, 0, 0, 0, " %s %d\n", lcp_types[type], ntohs(*(u16 *)(o + 2)));
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break;
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case 3: // Authentication-Protocol
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{
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int proto = ntohs(*(u16 *)(o + 2));
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log(4, 0, 0, 0, " %s %s\n", lcp_types[type],
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proto == 0xC223 ? "CHAP" : "PAP");
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break;
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}
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case 5: // Magic-Number
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{
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u32 magicno = ntohl(*(u32 *)(o + 2));
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log(4, 0, 0, 0, " %s %x\n", lcp_types[type], magicno);
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break;
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}
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case 4: // Quality-Protocol
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{
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u32 qp = ntohl(*(u32 *)(o + 2));
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log(4, 0, 0, 0, " %s %x\n", lcp_types[type], qp);
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break;
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}
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case 7: // Protocol-Field-Compression
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{
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u32 pfc = ntohl(*(u32 *)(o + 2));
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log(4, 0, 0, 0, " %s %x\n", lcp_types[type], pfc);
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break;
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}
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case 8: // Address-And-Control-Field-Compression
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{
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u32 afc = ntohl(*(u32 *)(o + 2));
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log(4, 0, 0, 0, " %s %x\n", lcp_types[type], afc);
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break;
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}
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default:
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log(2, 0, 0, 0, " Unknown PPP LCP Option type %d\n", type);
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break;
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}
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x -= length;
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o += length;
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}
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}
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// Process LCP messages
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void processlcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
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{
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u8 b[MAXCONTROL];
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u8 *q = NULL;
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#ifdef STAT_CALLS
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STAT(call_processlcp);
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#endif
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log_hex(5, "LCP", p, l);
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if (l < 4)
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{
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log(1, session[s].ip, s, t, "Short LCP %d bytes", l);
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STAT(tunnel_rx_errors);
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return ;
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}
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if (*p == ConfigAck)
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{
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log(3, session[s].ip, s, t, "LCP: Discarding ConfigAck\n");
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}
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else if (*p == ConfigReq)
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{
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signed int x = l - 1;
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char *o = (p + 1);
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log(3, session[s].ip, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
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while (x > 2)
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{
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int type = *(u8 *)(o);
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int length = *(u8 *)(o + 1);
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if (length == 0 || type == 0) break;
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switch (type)
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{
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case 1: // Maximum-Receive-Unit
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session[s].mru = ntohs(*(u16 *)(o + 2));
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break;
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case 3: // Authentication-Protocol
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{
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int proto = ntohs(*(u16 *)(o + 2));
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if (proto == 0xC223)
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{
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log(2, session[s].ip, s, t, " Remote end is trying to do CHAP. Rejecting it.\n");
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if (!q)
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{
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q = makeppp(b, p, l, t, s, PPPLCP);
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*q++ = ConfigNak;
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}
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memcpy(q, o, length);
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*(u16 *)(q += 2) = htons(0xC023); // NAK -> Use PAP instead
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q += length;
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}
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break;
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}
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case 5: // Magic-Number
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{
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// u32 magicno = ntohl(*(u32 *)(o + 2));
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break;
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}
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case 4: // Quality-Protocol
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{
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// u32 qp = ntohl(*(u32 *)(o + 2));
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break;
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}
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case 7: // Protocol-Field-Compression
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{
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// u32 pfc = ntohl(*(u32 *)(o + 2));
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break;
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}
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case 8: // Address-And-Control-Field-Compression
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{
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// u32 afc = ntohl(*(u32 *)(o + 2));
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break;
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}
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default:
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log(2, session[s].ip, s, t, " Unknown PPP LCP Option type %d\n", type);
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break;
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}
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x -= length;
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o += length;
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}
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if (!q)
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{
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// Send back a ConfigAck
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log(3, session[s].ip, s, t, "ConfigReq accepted, sending as Ack\n");
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q = makeppp(b, p, l, t, s, PPPLCP);
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*q = ConfigAck;
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tunnelsend(b, l + (q - b), t);
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}
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else
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{
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// Already built a ConfigNak... send it
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log(3, session[s].ip, s, t, "Sending ConfigNak\n");
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tunnelsend(b, l + (q - b), t);
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log(3, session[s].ip, s, t, "Sending ConfigReq, requesting PAP login\n");
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q = makeppp(b, NULL, 0, t, s, PPPLCP);
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*q++ = ConfigReq;
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*(u8 *)(q++) = 3;
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*(u8 *)(q++) = 4;
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*(u16 *)(q += 2) = htons(0xC023);
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tunnelsend(b, l + (q - b), t);
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}
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}
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else if (*p == ConfigNak)
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{
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log(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n");
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dumplcp(p, l);
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return ;
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}
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else if (*p == TerminateReq)
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{
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*p = TerminateAck; // close
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q = makeppp(b, p, l, t, s, PPPLCP);
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log(3, session[s].ip, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
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sessionshutdown(s, "Remote end closed connection.");
|
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tunnelsend(b, l + (q - b), t); // send it
|
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}
|
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else if (*p == TerminateReq)
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{
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sessionshutdown(s, "Remote end closed connection.");
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}
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else if (*p == EchoReq)
|
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{
|
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*p = EchoReply; // reply
|
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*(u32 *) (p + 4) = htonl(session[s].magic); // our magic number
|
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q = makeppp(b, p, l, t, s, PPPLCP);
|
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log(3, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
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tunnelsend(b, l + (q - b), t); // send it
|
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}
|
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else if (*p == EchoReply)
|
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{
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// Ignore it, last_packet time is set earlier than this.
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}
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else
|
||||
{
|
||||
log(1, session[s].ip, s, t, "Unexpected LCP code %d\n", *p);
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STAT(tunnel_rx_errors);
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return ;
|
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}
|
||||
}
|
||||
|
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// Process IPCP messages
|
||||
void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
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{
|
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#ifdef STAT_CALLS
|
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STAT(call_processipcp);
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#endif
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log_hex(5, "IPCP", p, l);
|
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if (l < 5)
|
||||
{
|
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log(1, 0, s, t, "Short IPCP %d bytes", l);
|
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STAT(tunnel_rx_errors);
|
||||
return ;
|
||||
}
|
||||
if (*p == ConfigAck)
|
||||
{ // happy with our IPCP
|
||||
u8 r = session[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
|
||||
return ; // done
|
||||
}
|
||||
if (*p != ConfigReq)
|
||||
{
|
||||
log(1, 0, s, t, "Unexpected IPCP code %d\n", *p);
|
||||
STAT(tunnel_rx_errors);
|
||||
return ;
|
||||
}
|
||||
if (ntohs(*(u16 *) (p + 2)) > l)
|
||||
{
|
||||
log(1, 0, s, t, "Length mismatch IPCP %d/%d\n", ntohs(*(u16 *) (p + 2)), l);
|
||||
STAT(tunnel_rx_errors);
|
||||
return ;
|
||||
}
|
||||
if (!session[s].ip)
|
||||
{
|
||||
log(3, 0, s, t, "Waiting on radius reply\n");
|
||||
return ; // have to wait on RADIUS eply
|
||||
}
|
||||
// form a config reply quoting the IP in the session
|
||||
{
|
||||
u8 b[MAXCONTROL];
|
||||
u8 *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
|
||||
u16 n = 4;
|
||||
i = p + l;
|
||||
q = makeppp(b, p, l, t, s, PPPIPCP);
|
||||
*q = ConfigRej;
|
||||
p += 4;
|
||||
while (p < i && p[1])
|
||||
{
|
||||
if (*p != 0x81 && *p != 0x83 && *p != 3)
|
||||
{
|
||||
log(2, 0, s, t, "IPCP reject %d\n", *p);
|
||||
memcpy(q + n, p, p[1]);
|
||||
n += p[1];
|
||||
}
|
||||
p += p[1];
|
||||
}
|
||||
*(u16 *) (q + 2) = htons(n);
|
||||
tunnelsend(b, n + (q - b), t); // send it
|
||||
}
|
||||
else
|
||||
{
|
||||
*p = ConfigAck;
|
||||
i = findppp(p, 0x81); // Primary DNS address
|
||||
if (i)
|
||||
{
|
||||
if (*(u32 *) (i + 2) != htonl(session[s].dns1))
|
||||
{
|
||||
*(u32 *) (i + 2) = htonl(session[s].dns1);
|
||||
*p = ConfigNak;
|
||||
}
|
||||
}
|
||||
i = findppp(p, 0x83); // Secondary DNS address (TBA, is it)
|
||||
if (i)
|
||||
{
|
||||
if (*(u32 *) (i + 2) != htonl(session[s].dns2))
|
||||
{
|
||||
*(u32 *) (i + 2) = htonl(session[s].dns2);
|
||||
*p = ConfigNak;
|
||||
}
|
||||
}
|
||||
i = findppp(p, 3); // IP address
|
||||
if (!i || i[1] != 6)
|
||||
{
|
||||
log(1, 0, s, t, "No IP in IPCP request\n");
|
||||
STAT(tunnel_rx_errors);
|
||||
return ;
|
||||
}
|
||||
if (*(u32 *) (i + 2) != htonl(session[s].ip))
|
||||
{
|
||||
*(u32 *) (i + 2) = htonl(session[s].ip);
|
||||
*p = ConfigNak;
|
||||
}
|
||||
q = makeppp(b, p, l, t, s, PPPIPCP);
|
||||
tunnelsend(b, l + (q - b), t); // send it
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// process IP packet received
|
||||
void processipin(tunnelidt t, sessionidt s, u8 * p, u16 l)
|
||||
{
|
||||
#ifdef STAT_CALLS
|
||||
STAT(call_processipin);
|
||||
#endif
|
||||
log_hex(5, "IP", p, l);
|
||||
|
||||
if (l > MAXETHER)
|
||||
{
|
||||
log(1, *(u32 *)(p + 12), s, t, "IP packet too long %d\n", l);
|
||||
STAT(tunnel_rx_errors);
|
||||
return ;
|
||||
}
|
||||
|
||||
session[s].cin += l;
|
||||
session[s].pin++;
|
||||
eth_tx += l;
|
||||
|
||||
// Add on the tun header
|
||||
p -= 4;
|
||||
*(u32 *)p = htonl(0x00000800);
|
||||
l += 4;
|
||||
|
||||
// Plugin hook
|
||||
{
|
||||
struct param_packet_rx packet = { &tunnel[t], &session[s], p, l };
|
||||
run_plugins(PLUGIN_PACKET_TX, &packet);
|
||||
}
|
||||
|
||||
// send to ethernet
|
||||
if (write(tapfd, p, l) < 0)
|
||||
{
|
||||
STAT(tap_tx_errors);
|
||||
log(0, 0, s, t, "Error writing %d bytes to TAP device: %s (tapfd=%d, p=%p)\n",
|
||||
l, strerror(errno), tapfd, p);
|
||||
}
|
||||
|
||||
if (session[s].snoop)
|
||||
{
|
||||
// Snooping this session, send it to ASIO
|
||||
snoop_send_packet(p, l);
|
||||
}
|
||||
STAT(tap_tx_packets);
|
||||
INC_STAT(tap_tx_bytes, l);
|
||||
}
|
||||
|
||||
// Process LCP messages
|
||||
void processccp(tunnelidt t, sessionidt s, u8 * p, u16 l)
|
||||
{
|
||||
#ifdef STAT_CALLS
|
||||
STAT(call_processccp);
|
||||
#endif
|
||||
log_hex(5, "CCP", p, l);
|
||||
if (l < 2 || (*p != ConfigReq && *p != TerminateReq))
|
||||
{
|
||||
log(1, 0, s, t, "Unexpecetd CCP request code %d\n", *p);
|
||||
STAT(tunnel_rx_errors);
|
||||
return ;
|
||||
}
|
||||
// reject
|
||||
{
|
||||
u8 b[MAXCONTROL];
|
||||
u8 *q;
|
||||
if (*p == ConfigReq)
|
||||
{
|
||||
if (l < 6)
|
||||
{
|
||||
*p = ConfigAck; // accept no compression
|
||||
}
|
||||
else
|
||||
{
|
||||
*p = ConfigRej; // reject
|
||||
}
|
||||
}
|
||||
else
|
||||
*p = TerminateAck; // close
|
||||
q = makeppp(b, p, l, t, s, PPPCCP);
|
||||
tunnelsend(b, l + (q - b), t); // send it
|
||||
}
|
||||
}
|
||||
|
||||
// send a CHAP PP packet
|
||||
void sendchap(tunnelidt t, sessionidt s)
|
||||
{
|
||||
u8 b[MAXCONTROL];
|
||||
u8 r = session[s].radius;
|
||||
u8 *q;
|
||||
#ifdef STAT_CALLS
|
||||
STAT(call_sendchap);
|
||||
#endif
|
||||
if (!r)
|
||||
{
|
||||
log(1, 0, s, t, "No RADIUS to send challenge\n");
|
||||
STAT(tunnel_tx_errors);
|
||||
return ;
|
||||
}
|
||||
log(1, 0, s, t, "Send CHAP challenge\n");
|
||||
{ // new challenge
|
||||
int n;
|
||||
for (n = 0; n < 15; n++)
|
||||
radius[r].auth[n] = rand();
|
||||
}
|
||||
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, "Timeout CHAP");
|
||||
STAT(tunnel_tx_errors);
|
||||
return ;
|
||||
}
|
||||
q = makeppp(b, 0, 0, t, s, PPPCHAP);
|
||||
*q = 1; // challenhe
|
||||
q[1] = radius[r].id; // ID
|
||||
q[4] = 16; // length
|
||||
memcpy(q + 5, radius[r].auth, 16); // challenge
|
||||
strcpy(q + 21, hostname); // our name
|
||||
*(u16 *) (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
|
||||
u8 *makeppp(u8 * b, u8 * p, int l, tunnelidt t, sessionidt s, u16 mtype)
|
||||
{
|
||||
*(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
|
||||
*(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel
|
||||
*(u16 *) (b + 4) = htons(session[s].far); // session
|
||||
b += 6;
|
||||
if (mtype != PPPLCP && !(session[s].flags & SESSIONACFC))
|
||||
{
|
||||
*(u16 *) b = htons(0xFF03); // HDLC header
|
||||
b += 2;
|
||||
}
|
||||
if (mtype < 0x100 && session[s].flags & SESSIONPFC)
|
||||
*b++ = mtype;
|
||||
else
|
||||
{
|
||||
*(u16 *) b = htons(mtype);
|
||||
b += 2;
|
||||
}
|
||||
if (p && l)
|
||||
memcpy(b, p, l);
|
||||
return b;
|
||||
}
|
||||
|
||||
// find a PPP option, returns point to option, or 0 if not found
|
||||
u8 *findppp(u8 * b, u8 mtype)
|
||||
{
|
||||
u16 l = ntohs(*(u16 *) (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;
|
||||
}
|
||||
|
||||
// Send initial LCP ConfigReq
|
||||
void initlcp(tunnelidt t, sessionidt s)
|
||||
{
|
||||
char b[500] = {0}, *q;
|
||||
|
||||
q = makeppp(b, NULL, 0, t, s, PPPLCP);
|
||||
log(4, 0, s, t, "Sending LCP ConfigReq for PAP\n");
|
||||
*q = ConfigReq;
|
||||
*(u8 *)(q + 1) = (time_now % 255) + 1; // ID
|
||||
*(u16 *)(q + 2) = htons(8); // Length
|
||||
*(u8 *)(q + 4) = 3;
|
||||
*(u8 *)(q + 5) = 4;
|
||||
*(u16 *)(q + 6) = htons(0xC023); // PAP
|
||||
tunnelsend(b, 12 + 8, t);
|
||||
}
|
||||
|
||||
Loading…
Add table
Add a link
Reference in a new issue