X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/4e0597cd50268bc57fa118f1362360a2db2ec23a..80308e88382d69baa14cef9b05b72d70263ec79a:/ppp.c diff --git a/ppp.c b/ppp.c index a0f7cc2..ad84be4 100644 --- a/ppp.c +++ b/ppp.c @@ -1,6 +1,6 @@ // L2TPNS PPP Stuff -char const *cvs_id_ppp = "$Id: ppp.c,v 1.21 2004-11-05 04:55:27 bodea Exp $"; +char const *cvs_id_ppp = "$Id: ppp.c,v 1.32 2004-11-28 20:10:04 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); @@ -275,46 +273,45 @@ void dumplcp(u8 *p, int l) else LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length); break; + case 2: // Async-Control-Character-Map + if (length == 6) + { + u32 asyncmap = ntohl(*(u32 *)(o + 2)); + LOG(4, 0, 0, 0, " %s %x\n", lcp_types[type], asyncmap); + } + else + LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length); + break; case 3: // Authentication-Protocol + if (length == 4) { - if (length == 4) - { - int proto = ntohs(*(u16 *)(o + 2)); - LOG(4, 0, 0, 0, " %s 0x%x (%s)\n", lcp_types[type], proto, - proto == PPPCHAP ? "CHAP" : - proto == PPPPAP ? "PAP" : "UNKNOWN"); - } - else - LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length); - break; + int proto = ntohs(*(u16 *)(o + 2)); + LOG(4, 0, 0, 0, " %s 0x%x (%s)\n", lcp_types[type], proto, + proto == PPPCHAP ? "CHAP" : + proto == PPPPAP ? "PAP" : "UNKNOWN"); } + else + LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length); + break; case 4: // Quality-Protocol { u32 qp = ntohl(*(u32 *)(o + 2)); LOG(4, 0, 0, 0, " %s %x\n", lcp_types[type], qp); - break; } + break; case 5: // Magic-Number + if (length == 6) { - if (length == 6) - { - u32 magicno = ntohl(*(u32 *)(o + 2)); - LOG(4, 0, 0, 0, " %s %x\n", lcp_types[type], magicno); - } - else - LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length); - break; + u32 magicno = ntohl(*(u32 *)(o + 2)); + LOG(4, 0, 0, 0, " %s %x\n", lcp_types[type], magicno); } + else + LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length); + break; case 7: // Protocol-Field-Compression - { - LOG(4, 0, 0, 0, " %s\n", lcp_types[type]); - break; - } case 8: // Address-And-Control-Field-Compression - { - LOG(4, 0, 0, 0, " %s\n", lcp_types[type]); - break; - } + LOG(4, 0, 0, 0, " %s\n", lcp_types[type]); + break; default: LOG(2, 0, 0, 0, " Unknown PPP LCP Option type %d\n", type); break; @@ -359,6 +356,7 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) { int x = l - 4; u8 *o = (p + 4); + u8 response = 0; LOG(3, session[s].ip, s, t, "LCP: ConfigReq (%d bytes)...\n", l); if (config->debug > 3) dumplcp(p, l); @@ -367,115 +365,135 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) { int type = o[0]; int length = o[1]; - if (length == 0 || type == 0) break; + if (length == 0 || type == 0 || x < length) break; switch (type) { case 1: // Maximum-Receive-Unit session[s].mru = ntohs(*(u16 *)(o + 2)); break; - case 2: // asyncmap - LOG_HEX(2, "PPP LCP Packet", p, l); - LOG(2, 0, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_types[(int)*p], ntohs( ((u16 *) p)[1]) ); + + case 2: // Async-Control-Character-Map + if (!ntohl(*(u32 *)(o + 2))) // all bits zero is OK + break; + + if (response && response != ConfigNak) // rej already queued + break; + + LOG(2, session[s].ip, s, t, " Remote requesting asyncmap. Rejecting.\n"); + if (!response) + { + 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 + q += 4; break; + case 3: // Authentication-Protocol { int proto = ntohs(*(u16 *)(o + 2)); + char proto_name[] = "0x0000"; + if (proto == PPPPAP) + break; + + if (response && response != ConfigNak) // rej already queued + break; + if (proto == PPPCHAP) + strcpy(proto_name, "CHAP"); + else + sprintf(proto_name, "%#4.4x", proto); + + LOG(2, session[s].ip, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name); + + if (!response) { - LOG(2, session[s].ip, s, t, " Remote end is trying to do CHAP. Rejecting it.\n"); - - if (!q) - { - 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++ = ConfigNak; - } - memcpy(q, o, length); - *(u16 *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead - q += length; + q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP); + if (!q) break; + response = *q++ = ConfigNak; } - break; + + 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; } + break; + case 5: // Magic-Number - { - magicno = ntohl(*(u32 *)(o + 2)); - break; - } + magicno = ntohl(*(u32 *)(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, 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), 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; - case 13: // CallBack option for LCP extention of win2000/routers L2TP client - case 17: - case 18: - { - // Reject LCP CallBack - LOG(2, session[s].ip, s, t, " PPP LCP Option type %d, len=%d\n", type, length); - memcpy(p + 4, o, length); - *(u16 *)(p + 2) = htons(length + 4); - *p = ConfigRej; - q = makeppp(b,sizeof(b), p, length + 4, t, s, PPPLCP); - tunnelsend(b, 12 + length + 4, t); - return; } - default: - // Reject Unknown LCP Option to stop to send it again - LOG(2, session[s].ip, s, t, " Unknown PPP LCP Option type %d\n", type); - memcpy(p + 4, o, length); - *(u16 *)(p + 2) = htons(length + 4); - *p = ConfigRej; - q = makeppp(b,sizeof(b), p, length + 4, t, s, PPPLCP); - tunnelsend(b, 12 + length + 4, t); - return; + memcpy(q, o, length); + q += length; } x -= length; o += length; } - if (!(session[s].flags & SF_LCP_ACKED)) - initlcp(t, s); - - if (!q) + if (!response) { // Send back a ConfigAck - LOG(3, session[s].ip, s, t, "ConfigReq accepted, sending as Ack\n"); 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; - } - *q = ConfigAck; - tunnelsend(b, l + (q - b), t); - } - else - { - // Already built a ConfigNak... send it - LOG(3, session[s].ip, s, t, "Sending ConfigNak\n"); - tunnelsend(b, l + (q - b), t); + if (!q) return; + response = *q = ConfigAck; } + + LOG(3, session[s].ip, s, t, "Sending %s\n", ppp_lcp_types[response]); + tunnelsend(b, l + (q - b), t); + + if (!(session[s].flags & SF_LCP_ACKED)) + initlcp(t, s); } 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) { @@ -483,14 +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) @@ -506,11 +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); } @@ -522,6 +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) { @@ -559,6 +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) @@ -594,10 +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]) @@ -651,10 +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 } } @@ -688,11 +719,9 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l) return; } - 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); - } + // 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; @@ -704,16 +733,6 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l) return; } - session[s].cin += l - 4; - session[s].total_cin += l - 4; - sess_count[s].cin += l - 4; - - session[s].pin++; - eth_tx += l - 4; - - STAT(tun_tx_packets); - INC_STAT(tun_tx_bytes, l); - if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets. tbf_queue_packet(session[s].tbf_in, p, l); return; @@ -725,8 +744,25 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l) STAT(tun_tx_errors); LOG(0, 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_count[s].cin += l - 4; + + session[s].pin++; + eth_tx += l - 4; + + STAT(tun_tx_packets); + INC_STAT(tun_tx_bytes, l - 4); } // @@ -736,11 +772,20 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l) void send_ipin(sessionidt s, u8 *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, 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 @@ -750,47 +795,61 @@ void send_ipin(sessionidt s, u8 *buf, int len) 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, 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)) + switch (l > 1 ? *p : 0) { - LOG(1, 0, s, t, "Unexpected CCP request code %d\n", *p); - STAT(tunnel_rx_errors); - return ; - } - // reject - { - 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 @@ -828,10 +887,8 @@ 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 @@ -846,8 +903,13 @@ 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 @@ -866,45 +928,28 @@ 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 @@ -915,19 +960,24 @@ 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; + + if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP))) + return; - q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP); + 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); } -