From 3462b32b6e0e864acbe79e5c91b2c6a50742013f Mon Sep 17 00:00:00 2001 From: Steven Barth Date: Wed, 16 Jul 2014 14:54:34 +0200 Subject: [PATCH 1/1] Initial rewrite of NDP proxy --- src/config.c | 25 ----- src/ndp.c | 321 ++++++++++++++++++++++------------------------------------- src/odhcpd.h | 4 +- 3 files changed, 118 insertions(+), 232 deletions(-) diff --git a/src/config.c b/src/config.c index 068d1a7..35d8af7 100644 --- a/src/config.c +++ b/src/config.c @@ -42,7 +42,6 @@ enum { IFACE_ATTR_PD_CER, IFACE_ATTR_NDPROXY_ROUTING, IFACE_ATTR_NDPROXY_SLAVE, - IFACE_ATTR_NDPROXY_STATIC, IFACE_ATTR_MAX }; @@ -73,14 +72,12 @@ static const struct blobmsg_policy iface_attrs[IFACE_ATTR_MAX] = { [IFACE_ATTR_RA_PREFERENCE] = { .name = "ra_preference", .type = BLOBMSG_TYPE_STRING }, [IFACE_ATTR_NDPROXY_ROUTING] = { .name = "ndproxy_routing", .type = BLOBMSG_TYPE_BOOL }, [IFACE_ATTR_NDPROXY_SLAVE] = { .name = "ndproxy_slave", .type = BLOBMSG_TYPE_BOOL }, - [IFACE_ATTR_NDPROXY_STATIC] = { .name = "ndproxy_static", .type = BLOBMSG_TYPE_ARRAY }, }; static const struct uci_blob_param_info iface_attr_info[IFACE_ATTR_MAX] = { [IFACE_ATTR_UPSTREAM] = { .type = BLOBMSG_TYPE_STRING }, [IFACE_ATTR_DNS] = { .type = BLOBMSG_TYPE_STRING }, [IFACE_ATTR_DOMAIN] = { .type = BLOBMSG_TYPE_STRING }, - [IFACE_ATTR_NDPROXY_STATIC] = { .type = BLOBMSG_TYPE_STRING }, }; const struct uci_blob_param_list interface_attr_list = { @@ -151,7 +148,6 @@ static void clean_interface(struct interface *iface) free(iface->dns); free(iface->search); free(iface->upstream); - free(iface->static_ndp); free(iface->dhcpv4_dns); free(iface->dhcpv6_raw); free(iface->filter_class); @@ -519,27 +515,6 @@ int config_parse_interface(void *data, size_t len, const char *name, bool overwr if ((c = tb[IFACE_ATTR_NDPROXY_SLAVE])) iface->external = blobmsg_get_bool(c); - if ((c = tb[IFACE_ATTR_NDPROXY_STATIC])) { - struct blob_attr *cur; - unsigned rem; - - blobmsg_for_each_attr(cur, c, rem) { - if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING || !blobmsg_check_attr(cur, NULL)) - continue; - - int len = blobmsg_data_len(cur); - iface->static_ndp = realloc(iface->static_ndp, iface->static_ndp_len + len); - if (!iface->static_ndp) - goto err; - - if (iface->static_ndp_len) - iface->static_ndp[iface->static_ndp_len - 1] = ' '; - - memcpy(&iface->static_ndp[iface->static_ndp_len], blobmsg_get_string(cur), len); - iface->static_ndp_len += len; - } - } - return 0; err: diff --git a/src/ndp.c b/src/ndp.c index 44884be..9840ed4 100644 --- a/src/ndp.c +++ b/src/ndp.c @@ -17,6 +17,7 @@ #include #include +#include #include #include #include @@ -36,18 +37,11 @@ static void handle_solicit(void *addr, void *data, size_t len, struct interface *iface, void *dest); static void handle_rtnetlink(void *addr, void *data, size_t len, struct interface *iface, void *dest); -static struct ndp_neighbor* find_neighbor(struct in6_addr *addr, bool strict); -static void modify_neighbor(struct in6_addr *addr, struct interface *iface, - bool add); static ssize_t ping6(struct in6_addr *addr, const struct interface *iface); -static struct list_head neighbors = LIST_HEAD_INIT(neighbors); -static size_t neighbor_count = 0; static uint32_t rtnl_seqid = 0; - static int ping_socket = -1; -static struct odhcpd_event ndp_event = {{.fd = -1}, handle_solicit}; static struct odhcpd_event rtnl_event = {{.fd = -1}, handle_rtnetlink}; @@ -116,105 +110,71 @@ int init_ndp(void) group = RTNLGRP_NEIGH; setsockopt(rtnl_event.uloop.fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group)); - // Synthesize initial neighbor events - struct { - struct nlmsghdr nh; - struct ndmsg ndm; - } req = { - {sizeof(req), RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP, - ++rtnl_seqid, 0}, - {.ndm_family = AF_INET6} - }; - send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT); - return 0; } int setup_ndp_interface(struct interface *iface, bool enable) { - struct packet_mreq mreq = {iface->ifindex, PACKET_MR_ALLMULTI, ETH_ALEN, {0}}; - setsockopt(ndp_event.uloop.fd, SOL_PACKET, PACKET_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); - - struct ndp_neighbor *c, *n; - list_for_each_entry_safe(c, n, &neighbors, head) - if (c->iface == iface && (c->timeout == 0 || iface->ndp != RELAYD_RELAY || !enable)) - modify_neighbor(&c->addr, c->iface, false); + char procbuf[64]; + snprintf(procbuf, sizeof(procbuf), "/proc/sys/net/ipv6/conf/%s/proxy_ndp", iface->ifname); + int procfd = open(procbuf, O_WRONLY); - if (enable && iface->ndp == RELAYD_RELAY) { - setsockopt(ndp_event.uloop.fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)); - - if (iface->static_ndp_len) { - char *entry = alloca(iface->static_ndp_len), *saveptr; - if (!entry) { - syslog(LOG_ERR, "Alloca failed for static NDP list"); - return -1; - } - memcpy(entry, iface->static_ndp, iface->static_ndp_len); - - for (entry = strtok_r(entry, " ", &saveptr); entry; entry = strtok_r(NULL, " ", &saveptr)) { - char *sep; - struct ndp_neighbor *n = malloc(sizeof(*n)); - if (!n) { - syslog(LOG_ERR, "Malloc failed for static NDP-prefix %s", entry); - return -1; - } - - n->iface = iface; - n->timeout = 0; - - sep = strchr(entry, '/'); - if (!sep) { - free(n); - syslog(LOG_ERR, "Invalid static NDP-prefix %s", entry); - return -1; - } - - *sep = 0; - n->len = atoi(sep + 1); - if (inet_pton(AF_INET6, entry, &n->addr) != 1 || n->len > 128) { - free(n); - syslog(LOG_ERR, "Invalid static NDP-prefix %s/%s", entry, sep + 1); - return -1; - } + if (iface->ndp_event.uloop.fd >= 0) { + uloop_fd_delete(&iface->ndp_event.uloop); + close(iface->ndp_event.uloop.fd); + iface->ndp_event.uloop.fd = -1; - list_add(&n->head, &neighbors); - } - } + write(procfd, "0\n", 2); } - bool enable_packet = false; - struct interface *i; - list_for_each_entry(i, &interfaces, head) { - if (i == iface && !enable) - continue; - - if (i->ndp == RELAYD_RELAY) - enable_packet = true; - } + if (enable && iface->ndp == RELAYD_RELAY) { + write(procfd, "1\n", 2); - if (enable_packet && ndp_event.uloop.fd < 0) { - // Create socket for intercepting NDP - int sock = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, - htons(ETH_P_ALL)); // ETH_P_ALL for ingress + egress + int sock = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, htons(ETH_P_IPV6)); if (sock < 0) { syslog(LOG_ERR, "Unable to open packet socket: %s", strerror(errno)); return -1; } +#ifdef PACKET_RECV_TYPE + int pktt = 1 << PACKET_MULTICAST; + setsockopt(sock, SOL_PACKET, PACKET_RECV_TYPE, &pktt, sizeof(pktt)); +#endif + if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER, &bpf_prog, sizeof(bpf_prog))) { syslog(LOG_ERR, "Failed to set BPF: %s", strerror(errno)); return -1; } - ndp_event.uloop.fd = sock; - odhcpd_register(&ndp_event); - } else if (!enable_packet && ndp_event.uloop.fd >= 0) { - close(ndp_event.uloop.fd); - ndp_event.uloop.fd = -1; + struct sockaddr_ll ll = { + .sll_family = AF_PACKET, + .sll_ifindex = iface->ifindex, + .sll_protocol = htons(ETH_P_IPV6), + }; + bind(sock, (struct sockaddr*)&ll, sizeof(ll)); + + struct packet_mreq mreq = {iface->ifindex, PACKET_MR_ALLMULTI, ETH_ALEN, {0}}; + setsockopt(sock, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)); + + iface->ndp_event.uloop.fd = sock; + iface->ndp_event.handle_dgram = handle_solicit; + odhcpd_register(&iface->ndp_event); + + // Dump neighbor events + struct { + struct nlmsghdr nh; + struct ndmsg ndm; + } req = { + {sizeof(req), RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP, + ++rtnl_seqid, 0}, + {.ndm_family = AF_INET6} + }; + send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT); } + close(procfd); return 0; } @@ -266,61 +226,14 @@ static void handle_solicit(void *addr, void *data, size_t len, uint8_t mac[6]; odhcpd_get_mac(iface, mac); - if (!memcmp(ll->sll_addr, mac, sizeof(mac)) && - ll->sll_pkttype != PACKET_OUTGOING) + if (!memcmp(ll->sll_addr, mac, sizeof(mac))) return; // Looped back - time_t now = time(NULL); - - struct ndp_neighbor *n = find_neighbor(&req->nd_ns_target, false); - if (n && (n->iface || abs(n->timeout - now) < 5)) { - syslog(LOG_DEBUG, "%s is on %s", ipbuf, - (n->iface) ? n->iface->ifname : ""); - if (!n->iface || n->iface == iface) - return; - - // Found on other interface, answer with advertisement - struct { - struct nd_neighbor_advert body; - struct nd_opt_hdr opt_ll_hdr; - uint8_t mac[6]; - } advert = { - .body = { - .nd_na_hdr = {ND_NEIGHBOR_ADVERT, - 0, 0, {{0}}}, - .nd_na_target = req->nd_ns_target, - }, - .opt_ll_hdr = {ND_OPT_TARGET_LINKADDR, 1}, - }; - - memcpy(advert.mac, mac, sizeof(advert.mac)); - advert.body.nd_na_flags_reserved = ND_NA_FLAG_ROUTER | - ND_NA_FLAG_SOLICITED; - - struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0}; - if (!ns_is_dad) // If not DAD, then unicast to source - dest.sin6_addr = ip6->ip6_src; - - // Linux seems to not honor IPV6_PKTINFO on raw-sockets, so work around - setsockopt(ping_socket, SOL_SOCKET, SO_BINDTODEVICE, - iface->ifname, sizeof(iface->ifname)); - struct iovec iov = {&advert, sizeof(advert)}; - odhcpd_send(ping_socket, &dest, &iov, 1, iface); - } else { - // Send echo to all other interfaces to see where target is on - // This will trigger neighbor discovery which is what we want. - // We will observe the neighbor cache to see results. - - ssize_t sent = 0; - struct interface *c; - list_for_each_entry(c, &interfaces, head) - if (iface->ndp == RELAYD_RELAY && iface != c && - (!ns_is_dad || !c->external == false)) - sent += ping6(&req->nd_ns_target, c); - - if (sent > 0) // Sent a ping, add pending neighbor entry - modify_neighbor(&req->nd_ns_target, NULL, true); - } + struct interface *c; + list_for_each_entry(c, &interfaces, head) + if (iface->ndp == RELAYD_RELAY && iface != c && + (!ns_is_dad || !c->external == false)) + ping6(&req->nd_ns_target, c); } @@ -384,74 +297,15 @@ static void setup_route(struct in6_addr *addr, struct interface *iface, odhcpd_setup_route(addr, 128, iface, NULL, add); } -static void free_neighbor(struct ndp_neighbor *n) -{ - setup_route(&n->addr, n->iface, false); - list_del(&n->head); - free(n); - --neighbor_count; -} - -static struct ndp_neighbor* find_neighbor(struct in6_addr *addr, bool strict) -{ - time_t now = time(NULL); - struct ndp_neighbor *n, *e; - list_for_each_entry_safe(n, e, &neighbors, head) { - if ((!strict && !odhcpd_bmemcmp(&n->addr, addr, n->len)) || - (n->len == 128 && IN6_ARE_ADDR_EQUAL(&n->addr, addr))) - return n; - - if (!n->iface && abs(n->timeout - now) >= 5) - free_neighbor(n); - } - return NULL; -} - - -// Modified our own neighbor-entries -static void modify_neighbor(struct in6_addr *addr, - struct interface *iface, bool add) -{ - if (!addr || (void*)addr == (void*)iface) - return; - - struct ndp_neighbor *n = find_neighbor(addr, true); - if (!add) { // Delete action - if (n && (!n->iface || n->iface == iface)) - free_neighbor(n); - } else if (!n) { // No entry yet, add one if possible - if (neighbor_count >= NDP_MAX_NEIGHBORS || - !(n = malloc(sizeof(*n)))) - return; - - n->len = 128; - n->addr = *addr; - n->iface = iface; - if (!n->iface) - time(&n->timeout); - list_add(&n->head, &neighbors); - ++neighbor_count; - setup_route(addr, n->iface, add); - } else if (n->iface == iface) { - if (!n->iface) - time(&n->timeout); - } else if (iface && (!n->iface || - (!iface->external && n->iface->external))) { - setup_route(addr, n->iface, false); - n->iface = iface; - setup_route(addr, n->iface, add); - } - // TODO: In case a host switches interfaces we might want - // to set its old neighbor entry to NUD_STALE and ping it - // on the old interface to confirm if the MACs match. -} - // Handler for neighbor cache entries from the kernel. This is our source // to learn and unlearn hosts on interfaces. static void handle_rtnetlink(_unused void *addr, void *data, size_t len, _unused struct interface *iface, _unused void *dest) { + bool dump_neigh = false; + struct in6_addr last_solicited = IN6ADDR_ANY_INIT; + for (struct nlmsghdr *nh = data; NLMSG_OK(nh, len); nh = NLMSG_NEXT(nh, len)) { struct rtmsg *rtm = NLMSG_DATA(nh); @@ -506,8 +360,61 @@ static void handle_rtnetlink(_unused void *addr, void *data, size_t len, (NUD_REACHABLE | NUD_STALE | NUD_DELAY | NUD_PROBE | NUD_PERMANENT | NUD_NOARP))); - if (iface->ndp == RELAYD_RELAY) - modify_neighbor(addr, iface, add); + if (iface->ndp == RELAYD_RELAY) { + // Replay change to all neighbor cache + struct { + struct nlmsghdr nh; + struct ndmsg ndm; + struct nlattr nla_dst; + struct in6_addr dst; + } req = { + {sizeof(req), RTM_DELNEIGH, NLM_F_REQUEST, + ++rtnl_seqid, 0}, + {.ndm_family = AF_INET6, .ndm_flags = NTF_PROXY}, + {sizeof(struct nlattr) + sizeof(struct in6_addr), NDA_DST}, + *addr + }; + + if (add) { + req.nh.nlmsg_type = RTM_NEWNEIGH; + req.nh.nlmsg_flags |= NLM_F_CREATE; + + struct interface *c; + list_for_each_entry(c, &interfaces, head) { + if (c->ndp == RELAYD_RELAY && iface != c) { + req.ndm.ndm_ifindex = c->ifindex; + send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT); + } + } + + setup_route(addr, iface, true); + } else { + if (nh->nlmsg_type == RTM_NEWNEIGH) { + // might be locally originating + if (!IN6_ARE_ADDR_EQUAL(&last_solicited, addr)) { + last_solicited = *addr; + + struct interface *c; + list_for_each_entry(c, &interfaces, head) + if (iface->ndp == RELAYD_RELAY && iface != c && + !c->external == false) + ping6(addr, c); + } + } else { + struct interface *c; + list_for_each_entry(c, &interfaces, head) { + if (c->ndp == RELAYD_RELAY && iface != c) { + req.ndm.ndm_ifindex = c->ifindex; + send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT); + } + } + setup_route(addr, iface, false); + + // also: dump to add proxies back in case it moved elsewhere + dump_neigh = true; + } + } + } if (is_addr && iface->ra == RELAYD_SERVER) raise(SIGUSR1); // Inform about a change in addresses @@ -530,11 +437,17 @@ static void handle_rtnetlink(_unused void *addr, void *data, size_t len, } } } + } - /* TODO: See if this is required for optimal operation - // Keep neighbor entries alive so we don't loose routes - */ - if (add && (ndm->ndm_state & NUD_STALE)) - ping6(addr, iface); + if (dump_neigh) { + struct { + struct nlmsghdr nh; + struct ndmsg ndm; + } req = { + {sizeof(req), RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP, + ++rtnl_seqid, 0}, + {.ndm_family = AF_INET6} + }; + send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT); } } diff --git a/src/odhcpd.h b/src/odhcpd.h index b2b38dc..1fe775e 100644 --- a/src/odhcpd.h +++ b/src/odhcpd.h @@ -118,6 +118,7 @@ struct interface { // DHCPv4 struct odhcpd_event dhcpv6_event; struct odhcpd_event dhcpv4_event; + struct odhcpd_event ndp_event; struct list_head dhcpv4_assignments; // Managed PD @@ -160,9 +161,6 @@ struct interface { void *dhcpv6_raw; size_t dhcpv6_raw_len; - char* static_ndp; - size_t static_ndp_len; - char *upstream; size_t upstream_len; -- 2.11.0