From 07c2fd4068eed5fe5ff06fb8eea7b481325cf41a Mon Sep 17 00:00:00 2001 From: Erik Ekman Date: Sun, 28 Jun 2015 12:54:35 +0200 Subject: [PATCH] Prepare server code for IPv6 listening socket Add a struct with multiple dns file descriptors (for IPv4 and IPv6) and pass this to required areas. Choose which descriptor to use when sending by looking at the destination address family. --- src/iodined.c | 150 +++++++++++++++++++++++++++++++------------------- 1 file changed, 94 insertions(+), 56 deletions(-) diff --git a/src/iodined.c b/src/iodined.c index fa9b874..8b32b66 100644 --- a/src/iodined.c +++ b/src/iodined.c @@ -95,12 +95,31 @@ static int debug; static char *__progname; #endif -static int read_dns(int, int, struct query *); -static void write_dns(int, struct query *, char *, int, char); -static void handle_full_packet(int, int, int); +/* Struct with IPv4 and IPv6 file descriptors. + * Need to be passed on down to tunneling code since we can get a + * packet on one fd meant for a user on the other. + */ +struct dnsfd { + int v4fd; + int v6fd; +}; + +static int read_dns(int fd, struct dnsfd *dns_fds, int tun_fd, struct query *q); +static void write_dns(int fd, struct query *q, char *data, int datalen, char downenc); +static void handle_full_packet(int tun_fd, struct dnsfd *dns_fds, int userid); + +static int +get_dns_fd(struct dnsfd *fds, struct sockaddr_storage *addr) +{ + if (addr->ss_family == AF_INET6) { + return fds->v6fd; + } + return fds->v4fd; +} /* Ask ipify.org webservice to get external ip */ -static int get_external_ip(struct in_addr *ip) +static int +get_external_ip(struct in_addr *ip) { int sock; struct addrinfo *addr; @@ -624,7 +643,7 @@ send_chunk_or_dataless(int dns_fd, int userid, struct query *q) } static int -tunnel_tun(int tun_fd, int dns_fd) +tunnel_tun(int tun_fd, struct dnsfd *dns_fds) { unsigned long outlen; struct ip *header; @@ -659,13 +678,17 @@ tunnel_tun(int tun_fd, int dns_fd) start_new_outpacket(userid, out, outlen); /* Start sending immediately if query is waiting */ - if (users[userid].q_sendrealsoon.id != 0) + if (users[userid].q_sendrealsoon.id != 0) { + int dns_fd = get_dns_fd(dns_fds, &users[userid].q_sendrealsoon.from); send_chunk_or_dataless(dns_fd, userid, &users[userid].q_sendrealsoon); - else if (users[userid].q.id != 0) + } else if (users[userid].q.id != 0) { + int dns_fd = get_dns_fd(dns_fds, &users[userid].q.from); send_chunk_or_dataless(dns_fd, userid, &users[userid].q); + } return outlen; } else { /* CONN_RAW_UDP */ + int dns_fd = get_dns_fd(dns_fds, &users[userid].q.from); send_raw(dns_fd, out, outlen, userid, RAW_HDR_CMD_DATA, &users[userid].q); return outlen; } @@ -742,7 +765,7 @@ process_downstream_ack(int userid, int down_seq, int down_frag) } static void -handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len) +handle_null_request(int tun_fd, int dns_fd, struct dnsfd *dns_fds, struct query *q, int domain_len) { struct in_addr tempip; char in[512]; @@ -1420,7 +1443,7 @@ handle_null_request(int tun_fd, int dns_fd, struct query *q, int domain_len) } if (upstream_ok && lastfrag) { /* packet is complete */ - handle_full_packet(tun_fd, dns_fd, userid); + handle_full_packet(tun_fd, dns_fds, userid); } /* If there is a query that must be returned real soon, do it. @@ -1594,13 +1617,14 @@ forward_query(int bind_fd, struct query *q) } static int -tunnel_bind(int bind_fd, int dns_fd) +tunnel_bind(int bind_fd, struct dnsfd *dns_fds) { char packet[64*1024]; struct sockaddr_storage from; socklen_t fromlen; struct fw_query *query; unsigned short id; + int dns_fd; int r; fromlen = sizeof(struct sockaddr); @@ -1630,6 +1654,7 @@ tunnel_bind(int bind_fd, int dns_fd) format_addr(&query->addr, query->addrlen), (id & 0xffff), r); } + dns_fd = get_dns_fd(dns_fds, &query->addr); if (sendto(dns_fd, packet, r, 0, (const struct sockaddr *) &(query->addr), query->addrlen) <= 0) { warn("forward reply error"); @@ -1639,14 +1664,14 @@ tunnel_bind(int bind_fd, int dns_fd) } static int -tunnel_dns(int tun_fd, int dns_fd, int bind_fd) +tunnel_dns(int tun_fd, int dns_fd, struct dnsfd *dns_fds, int bind_fd) { struct query q; int read; int domain_len; int inside_topdomain = 0; - if ((read = read_dns(dns_fd, tun_fd, &q)) <= 0) + if ((read = read_dns(dns_fd, dns_fds, tun_fd, &q)) <= 0) return 0; if (debug >= 2) { @@ -1694,7 +1719,7 @@ tunnel_dns(int tun_fd, int dns_fd, int bind_fd) case T_SRV: case T_TXT: /* encoding is "transparent" here */ - handle_null_request(tun_fd, dns_fd, &q, domain_len); + handle_null_request(tun_fd, dns_fd, dns_fds, &q, domain_len); break; case T_NS: handle_ns_request(dns_fd, &q); @@ -1712,7 +1737,7 @@ tunnel_dns(int tun_fd, int dns_fd, int bind_fd) } static int -tunnel(int tun_fd, int dns_fd, int bind_fd, int max_idle_time) +tunnel(int tun_fd, struct dnsfd *dns_fds, int bind_fd, int max_idle_time) { struct timeval tv; fd_set fds; @@ -1745,8 +1770,8 @@ tunnel(int tun_fd, int dns_fd, int bind_fd, int max_idle_time) FD_ZERO(&fds); - FD_SET(dns_fd, &fds); - maxfd = dns_fd; + FD_SET(dns_fds->v4fd, &fds); + maxfd = dns_fds->v4fd; if (bind_fd) { /* wait for replies from real DNS */ @@ -1783,15 +1808,15 @@ tunnel(int tun_fd, int dns_fd, int bind_fd, int max_idle_time) } } } - } else { - if (FD_ISSET(tun_fd, &fds)) { - tunnel_tun(tun_fd, dns_fd); - } - if (FD_ISSET(dns_fd, &fds)) { - tunnel_dns(tun_fd, dns_fd, bind_fd); - } + } else { + if (FD_ISSET(tun_fd, &fds)) { + tunnel_tun(tun_fd, dns_fds); + } + if (FD_ISSET(dns_fds->v4fd, &fds)) { + tunnel_dns(tun_fd, dns_fds->v4fd, dns_fds, bind_fd); + } if (FD_ISSET(bind_fd, &fds)) { - tunnel_bind(bind_fd, dns_fd); + tunnel_bind(bind_fd, dns_fds); } } @@ -1801,15 +1826,17 @@ tunnel(int tun_fd, int dns_fd, int bind_fd, int max_idle_time) users[userid].last_pkt + 60 > time(NULL) && users[userid].q_sendrealsoon.id != 0 && users[userid].conn == CONN_DNS_NULL && - !users[userid].q_sendrealsoon_new) + !users[userid].q_sendrealsoon_new) { + int dns_fd = get_dns_fd(dns_fds, &users[userid].q_sendrealsoon.from); send_chunk_or_dataless(dns_fd, userid, &users[userid].q_sendrealsoon); + } } return 0; } static void -handle_full_packet(int tun_fd, int dns_fd, int userid) +handle_full_packet(int tun_fd, struct dnsfd *dns_fds, int userid) { unsigned long outlen; char out[64*1024]; @@ -1838,10 +1865,13 @@ handle_full_packet(int tun_fd, int dns_fd, int userid) users[userid].inpacket.len); /* Start sending immediately if query is waiting */ - if (users[touser].q_sendrealsoon.id != 0) + if (users[touser].q_sendrealsoon.id != 0) { + int dns_fd = get_dns_fd(dns_fds, &users[touser].q_sendrealsoon.from); send_chunk_or_dataless(dns_fd, touser, &users[touser].q_sendrealsoon); - else if (users[touser].q.id != 0) + } else if (users[touser].q.id != 0) { + int dns_fd = get_dns_fd(dns_fds, &users[touser].q.from); send_chunk_or_dataless(dns_fd, touser, &users[touser].q); + } #ifdef OUTPACKETQ_LEN } else { save_to_outpacketq(touser, @@ -1850,6 +1880,7 @@ handle_full_packet(int tun_fd, int dns_fd, int userid) #endif } } else{ /* CONN_RAW_UDP */ + int dns_fd = get_dns_fd(dns_fds, &users[touser].q.from); send_raw(dns_fd, users[userid].inpacket.data, users[userid].inpacket.len, touser, RAW_HDR_CMD_DATA, &users[touser].q); @@ -1905,7 +1936,7 @@ handle_raw_login(char *packet, int len, struct query *q, int fd, int userid) } static void -handle_raw_data(char *packet, int len, struct query *q, int dns_fd, int tun_fd, int userid) +handle_raw_data(char *packet, int len, struct query *q, struct dnsfd *dns_fds, int tun_fd, int userid) { if (check_authenticated_user_and_ip(userid, q) != 0) { return; @@ -1926,7 +1957,7 @@ handle_raw_data(char *packet, int len, struct query *q, int dns_fd, int tun_fd, users[userid].inpacket.len, userid); } - handle_full_packet(tun_fd, dns_fd, userid); + handle_full_packet(tun_fd, dns_fds, userid); } static void @@ -1950,7 +1981,7 @@ handle_raw_ping(struct query *q, int dns_fd, int userid) } static int -raw_decode(char *packet, int len, struct query *q, int dns_fd, int tun_fd) +raw_decode(char *packet, int len, struct query *q, int dns_fd, struct dnsfd *dns_fds, int tun_fd) { int raw_user; @@ -1967,7 +1998,7 @@ raw_decode(char *packet, int len, struct query *q, int dns_fd, int tun_fd) break; case RAW_HDR_CMD_DATA: /* Data packet */ - handle_raw_data(&packet[RAW_HDR_LEN], len - RAW_HDR_LEN, q, dns_fd, tun_fd, raw_user); + handle_raw_data(&packet[RAW_HDR_LEN], len - RAW_HDR_LEN, q, dns_fds, tun_fd, raw_user); break; case RAW_HDR_CMD_PING: /* Keepalive packet */ @@ -1981,7 +2012,8 @@ raw_decode(char *packet, int len, struct query *q, int dns_fd, int tun_fd) } static int -read_dns(int fd, int tun_fd, struct query *q) /* FIXME: tun_fd is because of raw_decode() below */ +read_dns(int fd, struct dnsfd *dns_fds, int tun_fd, struct query *q) +/* FIXME: dns_fds and tun_fd are because of raw_decode() below */ { struct sockaddr_in from; socklen_t addrlen; @@ -2016,7 +2048,7 @@ read_dns(int fd, int tun_fd, struct query *q) /* FIXME: tun_fd is because of raw q->fromlen = addrlen; /* TODO do not handle raw packets here! */ - if (raw_decode(packet, r, q, fd, tun_fd)) { + if (raw_decode(packet, r, q, fd, dns_fds, tun_fd)) { return 0; } if (dns_decode(NULL, 0, q, QR_QUERY, packet, r) < 0) { @@ -2262,7 +2294,7 @@ int main(int argc, char **argv) { extern char *__progname; - char *listen_ip; + char *listen_ip4; char *errormsg; #ifndef WINDOWS32 struct passwd *pw; @@ -2273,7 +2305,7 @@ main(int argc, char **argv) char *context; char *device; char *pidfile; - int dnsd_fd; + struct dnsfd dns_fds; int tun_fd; /* settings for forwarding normal DNS to @@ -2289,8 +2321,8 @@ main(int argc, char **argv) int ns_get_externalip; int retval; int max_idle_time = 0; - struct sockaddr_storage dnsaddr; - int dnsaddr_len; + struct sockaddr_storage dns4addr; + int dns4addr_len; #ifdef HAVE_SYSTEMD int nb_fds; #endif @@ -2308,7 +2340,7 @@ main(int argc, char **argv) bind_fd = 0; mtu = 1130; /* Very many relays give fragsize 1150 or slightly higher for NULL; tun/zlib adds ~17 bytes. */ - listen_ip = NULL; + listen_ip4 = NULL; port = 53; ns_ip = INADDR_ANY; ns_get_externalip = 0; @@ -2374,7 +2406,7 @@ main(int argc, char **argv) mtu = atoi(optarg); break; case 'l': - listen_ip = optarg; + listen_ip4 = optarg; break; case 'p': port = atoi(optarg); @@ -2471,14 +2503,14 @@ main(int argc, char **argv) foreground = 1; } - dnsaddr_len = get_addr(listen_ip, port, AF_INET, AI_PASSIVE | AI_NUMERICHOST, &dnsaddr); - if (dnsaddr_len < 0) { + dns4addr_len = get_addr(listen_ip4, port, AF_INET, AI_PASSIVE | AI_NUMERICHOST, &dns4addr); + if (dns4addr_len < 0) { warnx("Bad IP address to listen on."); usage(); } if(bind_enable) { - in_addr_t dns_ip = ((struct sockaddr_in *) &dnsaddr)->sin_addr.s_addr; + in_addr_t dns_ip = ((struct sockaddr_in *) &dns4addr)->sin_addr.s_addr; if (bind_port < 1 || bind_port > 65535) { warnx("Bad DNS server port number given."); usage(); @@ -2526,30 +2558,36 @@ main(int argc, char **argv) if ((tun_fd = open_tun(device)) == -1) { retval = 1; - goto cleanup0; + goto cleanup_none; } if (!skipipconfig) { const char *other_ip = users_get_first_ip(); if (tun_setip(argv[0], other_ip, netmask) != 0 || tun_setmtu(mtu) != 0) { retval = 1; free((void*) other_ip); - goto cleanup1; + goto cleanup_tun; } free((void*) other_ip); } + + /* Mark both file descriptors as unused */ + dns_fds.v4fd = -1; + dns_fds.v6fd = -1; + #ifdef HAVE_SYSTEMD nb_fds = sd_listen_fds(0); if (nb_fds > 1) { retval = 1; warnx("Too many file descriptors received!\n"); - goto cleanup1; + goto cleanup_tun; } else if (nb_fds == 1) { - dnsd_fd = SD_LISTEN_FDS_START; + /* XXX: assume we get IPv4 socket */ + dns_fds.v4fd = SD_LISTEN_FDS_START; } else { #endif - if ((dnsd_fd = open_dns(&dnsaddr, dnsaddr_len)) < 0) { + if ((dns_fds.v4fd = open_dns(&dns4addr, dns4addr_len)) < 0) { retval = 1; - goto cleanup2; + goto cleanup_tun; } #ifdef HAVE_SYSTEMD } @@ -2557,7 +2595,7 @@ main(int argc, char **argv) if (bind_enable) { if ((bind_fd = open_dns_from_host(NULL, 0, AF_INET, 0)) < 0) { retval = 1; - goto cleanup3; + goto cleanup_dns4; } } @@ -2602,16 +2640,16 @@ main(int argc, char **argv) syslog(LOG_INFO, "started, listening on port %d", port); - tunnel(tun_fd, dnsd_fd, bind_fd, max_idle_time); + tunnel(tun_fd, &dns_fds, bind_fd, max_idle_time); syslog(LOG_INFO, "stopping"); -cleanup3: close_dns(bind_fd); -cleanup2: - close_dns(dnsd_fd); -cleanup1: +cleanup_dns4: + if (dns_fds.v4fd >= 0) + close_dns(dns_fds.v4fd); +cleanup_tun: close_tun(tun_fd); -cleanup0: +cleanup_none: return retval; }