X-Git-Url: https://git.decadent.org.uk/gitweb/?p=odhcp6c.git;a=blobdiff_plain;f=src%2Fra.c;h=1c121e63e3f8153064886293b3b8d5bcc72533b0;hp=c870279abae3f70730dc3aee17719a25168df726;hb=d21764d12bb799f89d42c94dc20d4adb6d588077;hpb=d77cbea57d1b7dd9c25421bb13c90e65bb54a6bc diff --git a/src/ra.c b/src/ra.c index c870279..1c121e6 100644 --- a/src/ra.c +++ b/src/ra.c @@ -1,5 +1,5 @@ /** - * Copyright (C) 2012-2013 Steven Barth + * Copyright (C) 2012-2014 Steven Barth * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License v2 as published by @@ -20,35 +20,90 @@ #include #include #include +#include +#include #include #include #include +#include #include #include #include +#ifndef SOL_NETLINK +#define SOL_NETLINK 270 +#endif + +#ifndef NETLINK_ADD_MEMBERSHIP +#define NETLINK_ADD_MEMBERSHIP 1 +#endif + +#ifndef IFF_LOWER_UP +#define IFF_LOWER_UP 0x10000 +#endif #include "odhcp6c.h" #include "ra.h" -static int sock = -1; -static unsigned if_index = 0; +static bool nocarrier = false; + +static int sock = -1, rtnl = -1; +static int if_index = 0; static char if_name[IF_NAMESIZE] = {0}; static volatile int rs_attempt = 0; static struct in6_addr lladdr = IN6ADDR_ANY_INIT; +struct { + struct icmp6_hdr hdr; + struct icmpv6_opt lladdr; +} rs = { + .hdr = {ND_ROUTER_SOLICIT, 0, 0, {{0}}}, + .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}}, +}; + + static void ra_send_rs(int signal __attribute__((unused))); int ra_init(const char *ifname, const struct in6_addr *ifid) { + const pid_t ourpid = getpid(); sock = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6); + if (sock < 0) + return -1; + if_index = if_nametoindex(ifname); + if (!if_index) + return -1; + strncpy(if_name, ifname, sizeof(if_name) - 1); lladdr = *ifid; + rtnl = socket(AF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_ROUTE); + if (rtnl < 0) + return -1; + + struct sockaddr_nl rtnl_kernel = { .nl_family = AF_NETLINK }; + if (connect(rtnl, (const struct sockaddr*)&rtnl_kernel, sizeof(rtnl_kernel)) < 0) + return -1; + + int val = RTNLGRP_LINK; + setsockopt(rtnl, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &val, sizeof(val)); + fcntl(rtnl, F_SETOWN, ourpid); + fcntl(rtnl, F_SETFL, fcntl(sock, F_GETFL) | O_ASYNC); + + struct { + struct nlmsghdr hdr; + struct ifinfomsg ifi; + } req = { + .hdr = {sizeof(req), RTM_GETLINK, NLM_F_REQUEST, 1, 0}, + .ifi = {.ifi_index = if_index} + }; + send(rtnl, &req, sizeof(req), 0); + ra_link_up(); + // Filter ICMPv6 package types struct icmp6_filter filt; ICMP6_FILTER_SETBLOCKALL(&filt); @@ -60,7 +115,7 @@ int ra_init(const char *ifname, const struct in6_addr *ifid) setsockopt(sock, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &an, sizeof(an)); // Let the kernel compute our checksums - int val = 2; + val = 2; setsockopt(sock, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val)); // This is required by RFC 4861 @@ -75,7 +130,6 @@ int ra_init(const char *ifname, const struct in6_addr *ifid) setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)); // Add async-mode - const pid_t ourpid = getpid(); fcntl(sock, F_SETOWN, ourpid); fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) | O_ASYNC); @@ -89,9 +143,16 @@ int ra_init(const char *ifname, const struct in6_addr *ifid) static void ra_send_rs(int signal __attribute__((unused))) { - const struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}}; const struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, if_index}; - sendto(sock, &rs, sizeof(rs), MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)); + const struct icmpv6_opt llnull = {ND_OPT_SOURCE_LINKADDR, 1, {0}}; + size_t len; + + if ((rs_attempt % 2 == 0) && memcmp(&rs.lladdr, &llnull, sizeof(llnull))) + len = sizeof(rs); + else + len = sizeof(struct icmp6_hdr); + + sendto(sock, &rs, len, MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)); if (++rs_attempt <= 3) alarm(4); @@ -101,21 +162,113 @@ static void ra_send_rs(int signal __attribute__((unused))) static int16_t pref_to_priority(uint8_t flags) { flags = (flags >> 3) & 0x03; - return (flags == 0x0) ? 1024 : (flags == 0x1) ? 512 : - (flags == 0x3) ? 2048 : -1; + return (flags == 0x0) ? 512 : (flags == 0x1) ? 384 : + (flags == 0x3) ? 640 : -1; +} + + +bool ra_link_up(void) +{ + static bool firstcall = true; + struct { + struct nlmsghdr hdr; + struct ifinfomsg msg; + uint8_t pad[4000]; + } resp; + + bool ret = false; + ssize_t read; + + do { + read = recv(rtnl, &resp, sizeof(resp), MSG_DONTWAIT); + if (read < 0 || !NLMSG_OK(&resp.hdr, (size_t)read) || + resp.hdr.nlmsg_type != RTM_NEWLINK || + resp.msg.ifi_index != if_index) + continue; + + ssize_t alen = NLMSG_PAYLOAD(&resp.hdr, sizeof(resp.msg)); + for (struct rtattr *rta = (struct rtattr*)(resp.pad); + RTA_OK(rta, alen); rta = RTA_NEXT(rta, alen)) { + if (rta->rta_type == IFLA_ADDRESS && + RTA_PAYLOAD(rta) >= sizeof(rs.lladdr.data)) + memcpy(rs.lladdr.data, RTA_DATA(rta), sizeof(rs.lladdr.data)); + } + + bool hascarrier = resp.msg.ifi_flags & IFF_LOWER_UP; + if (!firstcall && nocarrier != !hascarrier) + ret = true; + + nocarrier = !hascarrier; + firstcall = false; + } while (read > 0); + + if (ret) { + syslog(LOG_NOTICE, "carrier => %i event on %s", (int)!nocarrier, if_name); + + rs_attempt = 0; + ra_send_rs(SIGALRM); + } + + return ret; +} + +static bool ra_icmpv6_valid(struct sockaddr_in6 *source, int hlim, uint8_t *data, size_t len) +{ + struct icmp6_hdr *hdr = (struct icmp6_hdr*)data; + struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len]; + + if (hlim != 255 || len < sizeof(*hdr) || hdr->icmp6_code) + return false; + + switch (hdr->icmp6_type) { + case ND_ROUTER_ADVERT: + if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr)) + return false; + + opt = (struct icmpv6_opt*)((struct nd_router_advert*)data + 1); + break; + + default: + return false; + } + + icmpv6_for_each_option(opt, opt, end) + ; + + return opt == end; } +int ra_conf_hoplimit(int newvalue) +{ + static int value = 0; + if (newvalue > 0) + value = newvalue; + return value; +} -static void update_proc(const char *sect, const char *opt, uint32_t value) +int ra_conf_mtu(int newvalue) { - char buf[64]; - snprintf(buf, sizeof(buf), "/proc/sys/net/ipv6/%s/%s/%s", sect, if_name, opt); + static int value = 0; + if (newvalue >= 1280 && newvalue <= 65535) + value = newvalue; + return value; +} - int fd = open(buf, O_WRONLY); - write(fd, buf, snprintf(buf, sizeof(buf), "%u", value)); - close(fd); +int ra_conf_reachable(int newvalue) +{ + static int value = 0; + if (newvalue > 0 && newvalue <= 3600000) + value = newvalue; + return value; } +int ra_conf_retransmit(int newvalue) +{ + static int value = 0; + if (newvalue > 0 && newvalue <= 60000) + value = newvalue; + return value; +} bool ra_process(void) { @@ -123,34 +276,41 @@ bool ra_process(void) bool changed = false; uint8_t buf[1500], cmsg_buf[128]; struct nd_router_advert *adv = (struct nd_router_advert*)buf; - struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0}; + struct odhcp6c_entry *entry = alloca(sizeof(*entry) + 256); const struct in6_addr any = IN6ADDR_ANY_INIT; + memset(entry, 0, sizeof(*entry)); + if (IN6_IS_ADDR_UNSPECIFIED(&lladdr)) { - // Autodetect interface-id if not specified - FILE *fp = fopen("/proc/net/if_inet6", "r"); - if (fp) { - char addrbuf[33], ifbuf[16]; - while (fscanf(fp, "%32s %*x %*x %*x %*x %15s", addrbuf, ifbuf) == 2) { - if (!strcmp(ifbuf, if_name)) { - script_unhexlify((uint8_t*)&lladdr, sizeof(lladdr), addrbuf); - break; - } - } - fclose(fp); - } + struct sockaddr_in6 addr = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, if_index}; + socklen_t alen = sizeof(addr); + int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6); + + if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) && + !getsockname(sock, (struct sockaddr*)&addr, &alen)) + lladdr = addr.sin6_addr; + + close(sock); } while (true) { struct sockaddr_in6 from; struct iovec iov = {buf, sizeof(buf)}; - struct msghdr msg = {&from, sizeof(from), &iov, 1, - cmsg_buf, sizeof(cmsg_buf), 0}; + struct msghdr msg = { + .msg_name = (void *) &from, + .msg_namelen = sizeof(from), + .msg_iov = &iov, + .msg_iovlen = 1, + .msg_control = cmsg_buf, + .msg_controllen = sizeof(cmsg_buf), + .msg_flags = 0 + }; ssize_t len = recvmsg(sock, &msg, MSG_DONTWAIT); - if (len < 0) + if (len <= 0) break; - else if (len < (ssize_t)sizeof(*adv)) + + if (IN6_IS_ADDR_UNSPECIFIED(&lladdr)) continue; int hlim = 0; @@ -160,7 +320,7 @@ bool ra_process(void) ch->cmsg_type == IPV6_HOPLIMIT) memcpy(&hlim, CMSG_DATA(ch), sizeof(hlim)); - if (hlim != 255) + if (!ra_icmpv6_valid(&from, hlim, buf, len)) continue; // Stop sending solicits @@ -176,95 +336,120 @@ bool ra_process(void) uint32_t router_valid = ntohs(adv->nd_ra_router_lifetime); // Parse default route - entry.target = any; - entry.length = 0; - entry.router = from.sin6_addr; - entry.priority = pref_to_priority(adv->nd_ra_flags_reserved); - if (entry.priority < 0) - entry.priority = pref_to_priority(0); - entry.valid = router_valid; - entry.preferred = entry.valid; - changed |= odhcp6c_update_entry(STATE_RA_ROUTE, &entry); + entry->target = any; + entry->length = 0; + entry->router = from.sin6_addr; + entry->priority = pref_to_priority(adv->nd_ra_flags_reserved); + if (entry->priority < 0) + entry->priority = pref_to_priority(0); + entry->valid = router_valid; + entry->preferred = entry->valid; + changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry, 0, true); + + // Parse hoplimit + ra_conf_hoplimit(adv->nd_ra_curhoplimit); // Parse ND parameters - if (ntohl(adv->nd_ra_reachable) <= 3600000) - update_proc("neigh", "base_reachable_time_ms", ntohl(adv->nd_ra_reachable)); - - if (ntohl(adv->nd_ra_retransmit) <= 60000) - update_proc("neigh", "retrans_time_ms", ntohl(adv->nd_ra_retransmit)); - + ra_conf_reachable(ntohl(adv->nd_ra_reachable)); + ra_conf_retransmit(ntohl(adv->nd_ra_retransmit)); // Evaluate options struct icmpv6_opt *opt; icmpv6_for_each_option(opt, &adv[1], &buf[len]) { if (opt->type == ND_OPT_MTU) { uint32_t *mtu = (uint32_t*)&opt->data[2]; - if (ntohl(*mtu) >= 1280 && ntohl(*mtu) <= 65535) - update_proc("conf", "mtu", ntohl(*mtu)); + ra_conf_mtu(ntohl(*mtu)); } else if (opt->type == ND_OPT_ROUTE_INFORMATION && opt->len <= 3) { - entry.router = from.sin6_addr; - entry.target = any; - entry.priority = pref_to_priority(opt->data[1]); - entry.length = opt->data[0]; + entry->router = from.sin6_addr; + entry->target = any; + entry->priority = pref_to_priority(opt->data[1]); + entry->length = opt->data[0]; uint32_t *valid = (uint32_t*)&opt->data[2]; - entry.valid = ntohl(*valid); - memcpy(&entry.target, &opt->data[6], (opt->len - 1) * 8); + entry->valid = ntohl(*valid); + memcpy(&entry->target, &opt->data[6], (opt->len - 1) * 8); - if (entry.length > 128 || IN6_IS_ADDR_LINKLOCAL(&entry.target) - || IN6_IS_ADDR_LOOPBACK(&entry.target) - || IN6_IS_ADDR_MULTICAST(&entry.target)) + if (entry->length > 128 || IN6_IS_ADDR_LINKLOCAL(&entry->target) + || IN6_IS_ADDR_LOOPBACK(&entry->target) + || IN6_IS_ADDR_MULTICAST(&entry->target)) continue; - if (entry.priority > 0) - changed |= odhcp6c_update_entry(STATE_RA_ROUTE, &entry); + if (entry->priority > 0) + changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry, 0, true); } else if (opt->type == ND_OPT_PREFIX_INFORMATION && opt->len == 4) { struct nd_opt_prefix_info *pinfo = (struct nd_opt_prefix_info*)opt; - entry.router = any; - entry.target = pinfo->nd_opt_pi_prefix; - entry.priority = 256; - entry.length = pinfo->nd_opt_pi_prefix_len; - entry.valid = ntohl(pinfo->nd_opt_pi_valid_time); - entry.preferred = ntohl(pinfo->nd_opt_pi_preferred_time); - - if (entry.length > 128 || IN6_IS_ADDR_LINKLOCAL(&entry.target) - || IN6_IS_ADDR_LOOPBACK(&entry.target) - || IN6_IS_ADDR_MULTICAST(&entry.target) - || entry.valid < entry.preferred) + entry->router = any; + entry->target = pinfo->nd_opt_pi_prefix; + entry->priority = 256; + entry->length = pinfo->nd_opt_pi_prefix_len; + entry->valid = ntohl(pinfo->nd_opt_pi_valid_time); + entry->preferred = ntohl(pinfo->nd_opt_pi_preferred_time); + + if (entry->length > 128 || IN6_IS_ADDR_LINKLOCAL(&entry->target) + || IN6_IS_ADDR_LOOPBACK(&entry->target) + || IN6_IS_ADDR_MULTICAST(&entry->target) + || entry->valid < entry->preferred) continue; if (pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_ONLINK) - changed |= odhcp6c_update_entry_safe(STATE_RA_ROUTE, &entry, 7200); + changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry, 7200, true); if (!(pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_AUTO) || pinfo->nd_opt_pi_prefix_len != 64) continue; - entry.target.s6_addr32[2] = lladdr.s6_addr32[2]; - entry.target.s6_addr32[3] = lladdr.s6_addr32[3]; + entry->target.s6_addr32[2] = lladdr.s6_addr32[2]; + entry->target.s6_addr32[3] = lladdr.s6_addr32[3]; - changed |= odhcp6c_update_entry_safe(STATE_RA_PREFIX, &entry, 7200); + changed |= odhcp6c_update_entry(STATE_RA_PREFIX, entry, 7200, true); } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 2) { - entry.router = from.sin6_addr; - entry.priority = 0; - entry.length = 128; + entry->router = from.sin6_addr; + entry->priority = 0; + entry->length = 128; uint32_t *valid = (uint32_t*)&opt->data[2]; - entry.valid = ntohl(*valid); - entry.preferred = 0; + entry->valid = ntohl(*valid); + entry->preferred = 0; for (ssize_t i = 0; i < (opt->len - 1) / 2; ++i) { - memcpy(&entry.target, &opt->data[6 + i * sizeof(entry.target)], - sizeof(entry.target)); - changed |= odhcp6c_update_entry(STATE_RA_DNS, &entry); + memcpy(&entry->target, &opt->data[6 + i * sizeof(entry->target)], + sizeof(entry->target)); + changed |= odhcp6c_update_entry(STATE_RA_DNS, entry, 0, true); + } + } else if (opt->type == ND_OPT_DNSSL && opt->len > 1) { + uint32_t *valid = (uint32_t*)&opt->data[2]; + uint8_t *buf = &opt->data[6]; + uint8_t *end = &buf[(opt->len - 1) * 8]; + + entry->router = from.sin6_addr; + entry->valid = ntohl(*valid); + + while (buf < end) { + int len = dn_expand(buf, end, buf, (char*)entry->auxtarget, 256); + if (len < 1) + break; + + buf = &buf[len]; + entry->auxlen = strlen((char*)entry->auxtarget); + + if (entry->auxlen == 0) + continue; + + changed |= odhcp6c_update_entry(STATE_RA_SEARCH, entry, 0, true); + entry->auxlen = 0; } } } - size_t ra_dns_len; - struct odhcp6c_entry *entry = odhcp6c_get_state(STATE_RA_DNS, &ra_dns_len); - for (size_t i = 0; i < ra_dns_len / sizeof(*entry); ++i) - if (IN6_ARE_ADDR_EQUAL(&entry[i].router, &from.sin6_addr) && - entry[i].valid > router_valid) - entry[i].valid = router_valid; + int states[2] = {STATE_RA_DNS, STATE_RA_SEARCH}; + for (size_t i = 0; i < 2; ++i) { + size_t ra_dns_len; + uint8_t *start = odhcp6c_get_state(states[i], &ra_dns_len); + for (struct odhcp6c_entry *c = (struct odhcp6c_entry*)start; + (uint8_t*)c < &start[ra_dns_len] && &c->auxtarget[c->auxlen] <= &start[ra_dns_len]; + c = (struct odhcp6c_entry*)(&c->auxtarget[c->auxlen])) + if (IN6_ARE_ADDR_EQUAL(&c->router, &from.sin6_addr) && + c->valid > router_valid) + c->valid = router_valid; + } } if (found)