X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/df66283f1522c35ce692bee06c23c80413ce0791..0133cf7236592e66398a35e6aedddba71b755393:/ppp.c diff --git a/ppp.c b/ppp.c index 9ccb56f..d44ed25 100644 --- a/ppp.c +++ b/ppp.c @@ -1,6 +1,6 @@ // L2TPNS PPP Stuff -char const *cvs_id_ppp = "$Id: ppp.c,v 1.24 2004-11-09 05:48:28 bodea Exp $"; +char const *cvs_id_ppp = "$Id: ppp.c,v 1.31 2004-11-27 05:19:53 bodea Exp $"; #include #include @@ -21,9 +21,9 @@ extern int tunfd; extern char hostname[]; extern u32 eth_tx; extern time_t time_now; -extern struct configt *config; +extern configt *config; -void sendccp(tunnelidt t, sessionidt s); +static void initccp(tunnelidt t, sessionidt s); // Process PAP messages void processpap(tunnelidt t, sessionidt s, u8 *p, u16 l) @@ -75,10 +75,8 @@ void processpap(tunnelidt t, sessionidt s, u8 *p, u16 l) u8 b[MAXCONTROL]; u8 id = p[1]; u8 *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP); - if (!p) { // Failed to make ppp header! - LOG(1,0,0,0, "Failed to make PPP header in process pap!\n"); - return; - } + if (!p) return; + if (session[s].ip) *p = 2; // ACK else @@ -224,7 +222,7 @@ void processchap(tunnelidt t, sessionidt s, u8 *p, u16 l) radiussend(r, RADIUSAUTH); } -char *ppp_lcp_types[] = { +static char *ppp_lcp_types[] = { NULL, "ConfigReq", "ConfigAck", @@ -240,7 +238,7 @@ char *ppp_lcp_types[] = { "IdentRequest", }; -void dumplcp(u8 *p, int l) +static void dumplcp(u8 *p, int l) { int x = l - 4; u8 *o = (p + 4); @@ -384,14 +382,17 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) LOG(2, session[s].ip, s, t, " Remote requesting asyncmap. Rejecting.\n"); if (!response) { - q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(2, session[s].ip, s, t, " Failed to send packet.\n"); - break; - } + q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP); + if (!q) break; response = *q++ = ConfigNak; } + + if ((q - b + 11) > sizeof(b)) + { + LOG(2, session[s].ip, s, t, "LCP overflow for asyncmap ConfigNak.\n"); + break; + } + *q++ = type; *q++ = 6; memset(q, 0, 4); // asyncmap 0 @@ -417,14 +418,17 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) if (!response) { - q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(2, session[s].ip, s, t, " Failed to send packet.\n"); - break; - } + q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP); + if (!q) break; response = *q++ = ConfigNak; } + + if ((q - b + length) > sizeof(b)) + { + LOG(2, session[s].ip, s, t, "LCP overflow for %s ConfigNak.\n", proto_name); + break; + } + memcpy(q, o, length); *(u16 *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead q += length; @@ -444,15 +448,17 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) LOG(2, session[s].ip, s, t, " Rejecting PPP LCP Option type %d\n", type); if (!response || response != ConfigRej) // drop nak in favour of rej { - q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(2, session[s].ip, s, t, " Failed to send packet.\n"); - break; - } + q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP); + if (!q) return; response = *q++ = ConfigRej; } + if ((q - b + length) > sizeof(b)) + { + LOG(2, session[s].ip, s, t, "LCP overflow for ConfigRej (type=%d).\n", type); + break; + } + memcpy(q, o, length); q += length; } @@ -464,11 +470,7 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) { // Send back a ConfigAck q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(3, session[s].ip, s, t, " failed to create packet.\n"); - return; - } + if (!q) return; response = *q = ConfigAck; } @@ -480,22 +482,18 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) } else if (*p == ConfigNak) { - LOG(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n"); + LOG(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n"); if (config->debug > 3) dumplcp(p, l); return ; } else if (*p == TerminateReq) { + LOG(3, session[s].ip, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n"); *p = TerminateAck; // close q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(3, session[s].ip, s, t, "Failed to create PPP packet in processlcp.\n"); - return; - } - LOG(3, session[s].ip, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n"); - sessionshutdown(s, "Remote end closed connection."); + if (!q) return; tunnelsend(b, l + (q - b), t); // send it + sessionshutdown(s, "Remote end closed connection."); } else if (*p == TerminateAck) { @@ -503,15 +501,11 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) } else if (*p == EchoReq) { + LOG(5, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n"); *p = EchoReply; // reply *(u32 *) (p + 4) = htonl(session[s].magic); // our magic number q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(3, session[s].ip, s, t, " failed to send EchoReply.\n"); - return; - } - LOG(5, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n"); + if (!q) return; tunnelsend(b, l + (q - b), t); // send it } else if (*p == EchoReply) @@ -527,11 +521,7 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) l = 1400; } q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(3, session[s].ip, s, t, "Failed to create IdentRej.\n"); - return; - } + if (!q) return; LOG_HEX(5, "LCPIdentRej", q, l + 4); tunnelsend(b, 12 + 4 + l, t); } @@ -543,6 +533,26 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) } } +// find a PPP option, returns point to option, or 0 if not found +static 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; +} + // Process IPCP messages void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l) { @@ -580,6 +590,10 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l) session[s].flags |= SF_IPCP_ACKED; LOG(3, session[s].ip, 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) @@ -615,10 +629,8 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l) u16 n = 4; i = p + l; if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP))) - { - LOG(2, 0, s, t, "Failed to send IPCP ConfigRej\n"); return; - } + *q = ConfigRej; p += 4; while (p < i && p[1]) @@ -672,10 +684,8 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l) inet_toa(htonl(session[s].ip))); } if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP))) - { - LOG(2, 0, s, t, " Failed to send IPCP packet.\n"); return; - } + tunnelsend(b, l + (q - b), t); // send it } } @@ -783,48 +793,59 @@ void send_ipin(sessionidt s, u8 *buf, int len) eth_tx += len - 4; STAT(tun_tx_packets); - INC_STAT(tun_tx_bytes, l - 4); + INC_STAT(tun_tx_bytes, len - 4); } // Process CCP messages void processccp(tunnelidt t, sessionidt s, u8 *p, u16 l) { + u8 b[MAXCONTROL]; + u8 *q; CSTAT(call_processccp); LOG_HEX(5, "CCP", p, l); - if (l < 2 || (*p != ConfigReq && *p != TerminateReq)) - { - LOG(1, 0, s, t, "Unexpected CCP request code %d\n", *p); - STAT(tunnel_rx_errors); - return ; - } - // reject + switch (l > 1 ? *p : 0) { - u8 b[MAXCONTROL]; - u8 *q; - if (*p == ConfigReq) + case ConfigAck: + session[s].flags |= SF_CCP_ACKED; + return; + + case ConfigReq: + if (l < 6) // accept no compression { - if (l < 6) - { - *p = ConfigAck; // accept no compression - } - else - { - *p = ConfigRej; // reject - sendccp(t, s); - } + *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, 0, s, t, "Unexpected CCP request code %d\n", *p); else - *p = TerminateAck; // close - if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP))) - { - LOG(1,0,0,0, "Failed to send CCP packet.\n"); - return; - } - tunnelsend(b, l + (q - b), t); // send it + LOG(1, 0, 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 PP packet @@ -862,11 +883,8 @@ void sendchap(tunnelidt t, sessionidt s) return ; } q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP); - if (!q) - { - LOG(1, 0, s, t, "failed to send CHAP challenge.\n"); - return; - } + if (!q) return; + *q = 1; // challenge q[1] = radius[r].id; // ID q[4] = 16; // length @@ -881,8 +899,13 @@ void sendchap(tunnelidt t, sessionidt s) // returns start of PPP frame u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype) { - if (size < 12) - return NULL; // Need more space than this!! + if (size < 12) // Need more space than this!! + { + static int backtrace_count = 0; + LOG(0, session[s].ip, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size); + log_backtrace(backtrace_count, 5) + return NULL; + } *(u16 *) (b + 0) = htons(0x0002); // L2TP with no options *(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel @@ -901,46 +924,28 @@ u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype) b += 2; } - if (l + 12 > size) { - LOG(3,0,0,0, "Would have overflowed the buffer in makeppp: size %d, len %d.\n", size, l); - return NULL; // Run out of room to hold the packet! + if (l + 12 > size) + { + static int backtrace_count = 0; + LOG(2, session[s].ip, 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; -} -// 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; + return b; } -// Send initial LCP ConfigReq +// Send initial LCP ConfigReq for PAP, set magic no. void initlcp(tunnelidt t, sessionidt s) { - char b[500] = {0}, *q; + char b[500], *q; - q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP); - if (!q) - { - LOG(1, 0, s, t, "Failed to send LCP ConfigReq.\n"); + if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP))) return; - } + LOG(4, 0, s, t, "Sending LCP ConfigReq for PAP\n"); *q = ConfigReq; *(u8 *)(q + 1) = (time_now % 255) + 1; // ID @@ -951,19 +956,24 @@ void initlcp(tunnelidt t, sessionidt s) *(u8 *)(q + 10) = 3; *(u8 *)(q + 11) = 4; *(u16 *)(q + 12) = htons(PPPPAP); // PAP - tunnelsend(b, 12 + 14, t); + + LOG_HEX(5, "PPPLCP", q, 14); + tunnelsend(b, (q - b) + 14, t); } -// Send CCP reply -void sendccp(tunnelidt t, sessionidt s) +// Send CCP request for no compression +static void initccp(tunnelidt t, sessionidt s) { - char *q, b[500] = {0}; + char b[500], *q; - q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP); + if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP))) + return; + + LOG(4, 0, s, t, "Sending CCP ConfigReq for no compression\n"); *q = ConfigReq; *(u8 *)(q + 1) = (time_now % 255) + 1; // ID *(u16 *)(q + 2) = htons(4); // Length + LOG_HEX(5, "PPPCCP", q, 4); tunnelsend(b, (q - b) + 4 , t); } -