--- gvpe/src/vpn.C 2003/04/06 18:12:18 1.7 +++ gvpe/src/vpn.C 2004/04/02 14:42:45 1.24 @@ -1,5 +1,6 @@ /* vpn.C -- handle the protocol, encryption, handshaking etc. + Copyright (C) 2003-2004 Marc Lehmann This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -20,19 +21,20 @@ #include -#include -#include #include +#include +#include #include #include -#include #include -#include -#include #include #include #include +#include +#include + +#include "netcompat.h" #include "pidfile.h" @@ -40,6 +42,8 @@ #include "util.h" #include "vpn.h" +vpn network; // THE vpn (bad design...) + ///////////////////////////////////////////////////////////////////////////// const char *vpn::script_if_up () @@ -52,16 +56,13 @@ mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again char *env; - asprintf (&env, "CONFBASE=%s", confbase); - putenv (env); - asprintf (&env, "NODENAME=%s", THISNODE->nodename); - putenv (env); - asprintf (&env, "NODEID=%d", THISNODE->id); - putenv (env); - asprintf (&env, "IFNAME=%s", tap->interface ()); - putenv (env); - asprintf (&env, "MTU=%d", mtu); - putenv (env); + asprintf (&env, "CONFBASE=%s", confbase); putenv (env); + asprintf (&env, "NODENAME=%s", THISNODE->nodename); putenv (env); + asprintf (&env, "NODEID=%d", THISNODE->id); putenv (env); + asprintf (&env, "IFNAME=%s", tap->interface ()); putenv (env); + asprintf (&env, "IFTYPE=%s", IFTYPE); putenv (env); + asprintf (&env, "IFSUBTYPE=%s", IFSUBTYPE); putenv (env); + asprintf (&env, "MTU=%d", mtu); putenv (env); asprintf (&env, "MAC=%02x:%02x:%02x:%02x:%02x:%02x", 0xfe, 0xfd, 0x80, 0x00, THISNODE->id >> 8, THISNODE->id & 0xff); @@ -73,30 +74,56 @@ int vpn::setup () { + ipv4_fd = -1; + + if (THISNODE->protocols & PROT_IPv4 && ::conf.ip_proto) + { + ipv4_fd = socket (PF_INET, SOCK_RAW, ::conf.ip_proto); + + if (ipv4_fd < 0) + return -1; + + fcntl (ipv4_fd, F_SETFL, O_NONBLOCK); + +#if defined(SOL_IP) && defined(IP_MTU_DISCOVER) + // this I really consider a linux bug. I am neither connected + // nor do I fragment myself. Linux still sets DF and doesn't + // fragment for me sometimes. + { + int oval = IP_PMTUDISC_DONT; + setsockopt (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval); + } +#endif + + sockinfo si (THISNODE, PROT_IPv4); + + if (bind (ipv4_fd, si.sav4 (), si.salenv4 ())) + { + slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno)); + exit (EXIT_FAILURE); + } + + ipv4_ev_watcher.start (ipv4_fd, EVENT_READ); + } + udpv4_fd = -1; - if (THISNODE->protocols & PROT_UDPv4) + if (THISNODE->protocols & PROT_UDPv4 && THISNODE->udp_port) { udpv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP); if (udpv4_fd < 0) return -1; + fcntl (udpv4_fd, F_SETFL, O_NONBLOCK); + // standard daemon practise... { int oval = 1; setsockopt (udpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval); } - sockinfo si (THISNODE, PROT_UDPv4); - - if (bind (udpv4_fd, si.sav4 (), si.salenv4 ())) - { - slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno)); - exit (1); - } - -#ifdef IP_MTU_DISCOVER +#if defined(SOL_IP) && defined(IP_MTU_DISCOVER) // this I really consider a linux bug. I am neither connected // nor do I fragment myself. Linux still sets DF and doesn't // fragment for me sometimes. @@ -106,46 +133,74 @@ } #endif - udpv4_ev_watcher.start (udpv4_fd, POLLIN); + sockinfo si (THISNODE, PROT_UDPv4); + + if (bind (udpv4_fd, si.sav4 (), si.salenv4 ())) + { + slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno)); + exit (EXIT_FAILURE); + } + + udpv4_ev_watcher.start (udpv4_fd, EVENT_READ); } - ipv4_fd = -1; - if (THISNODE->protocols & PROT_IPv4) + icmpv4_fd = -1; + +#if ENABLE_ICMP + if (THISNODE->protocols & PROT_ICMPv4) { - ipv4_fd = socket (PF_INET, SOCK_RAW, ::conf.ip_proto); + icmpv4_fd = socket (PF_INET, SOCK_RAW, IPPROTO_ICMP); - if (ipv4_fd < 0) + if (icmpv4_fd < 0) return -1; - sockinfo si (THISNODE, PROT_IPv4); + fcntl (icmpv4_fd, F_SETFL, O_NONBLOCK); - if (bind (ipv4_fd, si.sav4 (), si.salenv4 ())) - { - slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno)); - exit (1); - } +#ifdef ICMP_FILTER + { + icmp_filter oval; + oval.data = 0xffffffff; + if (::conf.icmp_type < 32) + oval.data &= ~(1 << ::conf.icmp_type); -#ifdef IP_MTU_DISCOVER + setsockopt (icmpv4_fd, SOL_RAW, ICMP_FILTER, &oval, sizeof oval); + } +#endif + +#if defined(SOL_IP) && defined(IP_MTU_DISCOVER) // this I really consider a linux bug. I am neither connected // nor do I fragment myself. Linux still sets DF and doesn't // fragment for me sometimes. { int oval = IP_PMTUDISC_DONT; - setsockopt (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval); + setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval); } #endif - ipv4_ev_watcher.start (ipv4_fd, POLLIN); + sockinfo si (THISNODE, PROT_ICMPv4); + + if (bind (icmpv4_fd, si.sav4 (), si.salenv4 ())) + { + slog (L_ERR, _("can't bind icmpv4 on %s: %s"), (const char *)si, strerror (errno)); + exit (EXIT_FAILURE); + } + + icmpv4_ev_watcher.start (icmpv4_fd, EVENT_READ); } +#endif + + tcpv4_fd = -1; #if ENABLE_TCP - if (THISNODE->protocols & PROT_TCPv4) + if (THISNODE->protocols & PROT_TCPv4 && THISNODE->tcp_port) { tcpv4_fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP); if (tcpv4_fd < 0) return -1; + fcntl (tcpv4_fd, F_SETFL, O_NONBLOCK); + // standard daemon practise... { int oval = 1; @@ -157,16 +212,42 @@ if (bind (tcpv4_fd, si.sav4 (), si.salenv4 ())) { slog (L_ERR, _("can't bind tcpv4 on %s: %s"), (const char *)si, strerror (errno)); - exit (1); + exit (EXIT_FAILURE); } if (listen (tcpv4_fd, 5)) { slog (L_ERR, _("can't listen tcpv4 on %s: %s"), (const char *)si, strerror (errno)); - exit (1); + exit (EXIT_FAILURE); } - tcpv4_ev_watcher.start (tcpv4_fd, POLLIN); + tcpv4_ev_watcher.start (tcpv4_fd, EVENT_READ); + } +#endif + +#if ENABLE_DNS + if (THISNODE->protocols & PROT_DNSv4) + { + dnsv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP); + + if (dnsv4_fd < 0) + return -1; + + // standard daemon practise... + { + int oval = 1; + setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval); + } + + sockinfo si (THISNODE, PROT_DNSv4); + + if (bind (dnsv4_fd, si.sav4 (), si.salenv4 ())) + { + slog (L_ERR, _("can't bind dnsv4 on %s: %s"), (const char *)si, strerror (errno)); + exit (EXIT_FAILURE); + } + + dnsv4_ev_watcher.start (dnsv4_fd, EVENT_READ); } #endif @@ -174,12 +255,12 @@ if (!tap) //D this, of course, never catches { slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname); - exit (1); + exit (EXIT_FAILURE); } run_script (run_script_cb (this, &vpn::script_if_up), true); - tap_ev_watcher.start (tap->fd, POLLIN); + tap_ev_watcher.start (tap->fd, EVENT_READ); reconnect_all (); @@ -203,6 +284,16 @@ return send_tcpv4_packet (pkt, si, tos); #endif +#if ENABLE_ICMP + case PROT_ICMPv4: + return send_icmpv4_packet (pkt, si, tos); +#endif + +#if ENABLE_DNS + case PROT_DNSv4: + return send_dnsv4_packet (pkt, si, tos); +#endif + default: slog (L_CRIT, _("%s: FATAL: trying to send packet with unsupported protocol"), (const char *)si); return false; @@ -212,22 +303,90 @@ bool vpn::send_ipv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) { +#if defined(SOL_IP) && defined(IP_TOS) setsockopt (ipv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos); +#endif sendto (ipv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ()); return true; } +static u16 +ipv4_checksum (u16 *data, unsigned int len) +{ + // use 32 bit accumulator and fold back carry bits at the end + u32 sum = 0; + + while (len > 1) + { + sum += *data++; + len -= 2; + } + + // odd byte left? + if (len) + sum += *(u8 *)data; + + // add back carry bits + sum = (sum >> 16) + (sum & 0xffff); // lo += hi + sum += (sum >> 16); // carry + + return ~sum; +} + +#if ENABLE_ICMP +bool +vpn::send_icmpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) +{ +#if defined(SOL_IP) && defined(IP_TOS) + setsockopt (icmpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos); +#endif + + pkt->unshift_hdr (4); + + icmp_header *hdr = (icmp_header *)&((*pkt)[0]); + hdr->type = ::conf.icmp_type; + hdr->code = 255; + hdr->checksum = 0; + hdr->checksum = ipv4_checksum ((u16 *)hdr, pkt->len); + + sendto (icmpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ()); + + return true; +} +#endif + bool vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) { +#if defined(SOL_IP) && defined(IP_TOS) setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos); +#endif sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ()); return true; } void +vpn::inject_data_packet (tap_packet *pkt, int dst) +{ + if (dst) + { + // unicast + if (dst != THISNODE->id) + conns[dst - 1]->inject_data_packet (pkt); + } + else + { + // broadcast, this is ugly, but due to the security policy + // we have to connect to all hosts... + for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c) + if ((*c)->conf != THISNODE) + (*c)->inject_data_packet (pkt, true); + } +} + +void vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi) { unsigned int src = pkt->src (); @@ -248,10 +407,10 @@ { connection *c = conns[src - 1]; - if (dst == 0 && !THISNODE->routerprio) - slog (L_WARN, _("%s(%s): received broadcast, but we are no router"), + if (dst == 0) + slog (L_WARN, _("%s(%s): received broadcast (protocol violation)"), c->conf->nodename, (const char *)rsi); - else if (dst != 0 && dst != THISNODE->id) + else if (dst != THISNODE->id) { if (THISNODE->routerprio) // the tos setting gets lost here. who cares. @@ -268,9 +427,9 @@ } void -vpn::udpv4_ev (io_watcher &w, short revents) +vpn::ipv4_ev (io_watcher &w, short revents) { - if (revents & (POLLIN | POLLERR)) + if (revents & EVENT_READ) { vpn_packet *pkt = new vpn_packet; struct sockaddr_in sa; @@ -279,41 +438,40 @@ len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); - sockinfo si(sa, PROT_UDPv4); + sockinfo si(sa, PROT_IPv4); if (len > 0) { pkt->len = len; + // raw sockets deliver the ipv4, but don't expect it on sends + // this is slow, but... + pkt->skip_hdr (IP_OVERHEAD); + recv_vpn_packet (pkt, si); } else { // probably ECONNRESET or somesuch - slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno)); + slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno)); } delete pkt; } - else if (revents & POLLHUP) - { - // this cannot ;) happen on udp sockets - slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating.")); - exit (1); - } else { slog (L_ERR, _("FATAL: unknown revents %08x in socket, terminating\n"), revents); - exit (1); + exit (EXIT_FAILURE); } } +#if ENABLE_ICMP void -vpn::ipv4_ev (io_watcher &w, short revents) +vpn::icmpv4_ev (io_watcher &w, short revents) { - if (revents & (POLLIN | POLLERR)) + if (revents & EVENT_READ) { vpn_packet *pkt = new vpn_packet; struct sockaddr_in sa; @@ -322,17 +480,23 @@ len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); - sockinfo si(sa, PROT_IPv4); + sockinfo si(sa, PROT_ICMPv4); if (len > 0) { pkt->len = len; - // raw sockets deliver the ipv4, but don't expect it on sends - // this is slow, but... - pkt->skip_hdr (IP_OVERHEAD); + icmp_header *hdr = (icmp_header *)&((*pkt)[IP_OVERHEAD]); - recv_vpn_packet (pkt, si); + if (hdr->type == ::conf.icmp_type + && hdr->code == 255) + { + // raw sockets deliver the ipv4, but don't expect it on sends + // this is slow, but... + pkt->skip_hdr (ICMP_OVERHEAD); + + recv_vpn_packet (pkt, si); + } } else { @@ -342,77 +506,91 @@ delete pkt; } - else if (revents & POLLHUP) + else + { + slog (L_ERR, + _("FATAL: unknown revents %08x in socket, terminating\n"), + revents); + exit (EXIT_FAILURE); + } +} +#endif + +void +vpn::udpv4_ev (io_watcher &w, short revents) +{ + if (revents & EVENT_READ) { - // this cannot ;) happen on udp sockets - slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating.")); - exit (1); + vpn_packet *pkt = new vpn_packet; + struct sockaddr_in sa; + socklen_t sa_len = sizeof (sa); + int len; + + len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); + + sockinfo si(sa, PROT_UDPv4); + + if (len > 0) + { + pkt->len = len; + + recv_vpn_packet (pkt, si); + } + else + { + // probably ECONNRESET or somesuch + slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno)); + } + + delete pkt; } else { slog (L_ERR, _("FATAL: unknown revents %08x in socket, terminating\n"), revents); - exit (1); + exit (EXIT_FAILURE); } } void vpn::tap_ev (io_watcher &w, short revents) { - if (revents & POLLIN) + if (revents & EVENT_READ) { /* process data */ tap_packet *pkt; pkt = tap->recv (); - int dst = mac2id (pkt->dst); - int src = mac2id (pkt->src); + if (!pkt) + return; - if (src != THISNODE->id) + if (pkt->len > 14) { - slog (L_ERR, _("FATAL: tap packet not originating on current node received, terminating.")); - exit (1); - } + int dst = mac2id (pkt->dst); + int src = mac2id (pkt->src); - if (dst == THISNODE->id) - { - slog (L_ERR, _("FATAL: tap packet destined for current node received, terminating.")); - exit (1); - } - - if (dst > conns.size ()) - slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst); - else - { - if (dst) + if (src != THISNODE->id) { - // unicast - if (dst != THISNODE->id) - conns[dst - 1]->inject_data_packet (pkt); + slog (L_ERR, _("FATAL: tap packet not originating on current node received, exiting.")); + exit (EXIT_FAILURE); } - else - { - // broadcast, first check router, then self, then english - connection *router = find_router (); - if (router) - router->inject_data_packet (pkt, true); - else - for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c) - if ((*c)->conf != THISNODE) - (*c)->inject_data_packet (pkt); + if (dst == THISNODE->id) + { + slog (L_ERR, _("FATAL: tap packet destined for current node received, exiting.")); + exit (EXIT_FAILURE); } + + if (dst > conns.size ()) + slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst); + else + inject_data_packet (pkt, dst); } delete pkt; } - else if (revents & (POLLHUP | POLLERR)) - { - slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating.")); - exit (1); - } else abort (); } @@ -427,12 +605,9 @@ slog (L_INFO, _("preparing shutdown...")); shutdown_all (); - - remove_pid (pidfilename); - + remove_pid (conf.pidfilename); slog (L_INFO, _("terminating")); - - exit (0); + exit (EXIT_SUCCESS); } if (events & EVENT_RECONNECT) @@ -444,8 +619,6 @@ events = 0; } - - w.at = TSTAMP_CANCEL; } void @@ -479,7 +652,7 @@ connection *vpn::find_router () { - u32 prio = 0; + u32 prio = 1; connection *router = 0; for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i) @@ -487,9 +660,9 @@ connection *c = *i; if (c->conf->routerprio > prio - && c->connectmode == conf_node::C_ALWAYS - && c->conf != THISNODE - && c->ictx && c->octx) + && c->connectmode == conf_node::C_ALWAYS // so we don't drop the connection if in use + && c->ictx && c->octx + && c->conf != THISNODE) // redundant, since ictx==octx==0 always on thisnode { prio = c->conf->routerprio; router = c; @@ -508,7 +681,7 @@ else // no router found, aggressively connect to all routers for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i) - if ((*i)->conf->routerprio) + if ((*i)->conf->routerprio && (*i)->conf != THISNODE) (*i)->establish_connection (); } @@ -536,13 +709,19 @@ } vpn::vpn (void) -: event(this, &vpn::event_cb) -, udpv4_ev_watcher(this, &vpn::udpv4_ev) -, ipv4_ev_watcher (this, &vpn::ipv4_ev) -, tap_ev_watcher (this, &vpn::tap_ev) +: event (this, &vpn::event_cb) +, udpv4_ev_watcher (this, &vpn::udpv4_ev) +, ipv4_ev_watcher (this, &vpn::ipv4_ev) #if ENABLE_TCP -, tcpv4_ev_watcher(this, &vpn::tcpv4_ev) +, tcpv4_ev_watcher (this, &vpn::tcpv4_ev) +#endif +#if ENABLE_ICMP +, icmpv4_ev_watcher(this, &vpn::icmpv4_ev) +#endif +#if ENABLE_DNS +, dnsv4_ev_watcher (this, &vpn::dnsv4_ev) #endif +, tap_ev_watcher (this, &vpn::tap_ev) { }