/* Kernel communication using netlink interface. * Copyright (C) 1999 Kunihiro Ishiguro * * This file is part of GNU Zebra. * * GNU Zebra is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2, or (at your option) any * later version. * * GNU Zebra is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; see the file COPYING; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include #ifdef HAVE_NETLINK #include "linklist.h" #include "if.h" #include "log.h" #include "prefix.h" #include "connected.h" #include "table.h" #include "memory.h" #include "zebra_memory.h" #include "rib.h" #include "thread.h" #include "privs.h" #include "nexthop.h" #include "vrf.h" #include "mpls.h" #include "lib_errors.h" //#include "zebra/zserv.h" #include "zebra/zebra_router.h" #include "zebra/zebra_ns.h" #include "zebra/zebra_vrf.h" #include "zebra/rt.h" #include "zebra/debug.h" #include "zebra/kernel_netlink.h" #include "zebra/rt_netlink.h" #include "zebra/if_netlink.h" #include "zebra/rule_netlink.h" #include "zebra/zebra_errors.h" #ifndef SO_RCVBUFFORCE #define SO_RCVBUFFORCE (33) #endif /* Hack for GNU libc version 2. */ #ifndef MSG_TRUNC #define MSG_TRUNC 0x20 #endif /* MSG_TRUNC */ #ifndef NLMSG_TAIL #define NLMSG_TAIL(nmsg) \ ((struct rtattr *)(((uint8_t *)(nmsg)) \ + NLMSG_ALIGN((nmsg)->nlmsg_len))) #endif #ifndef RTA_TAIL #define RTA_TAIL(rta) \ ((struct rtattr *)(((uint8_t *)(rta)) + RTA_ALIGN((rta)->rta_len))) #endif #ifndef RTNL_FAMILY_IP6MR #define RTNL_FAMILY_IP6MR 129 #endif #ifndef RTPROT_MROUTED #define RTPROT_MROUTED 17 #endif #define NL_DEFAULT_BATCH_BUFSIZE (16 * NL_PKT_BUF_SIZE) /* * We limit the batch's size to a number smaller than the length of the * underlying buffer since the last message that wouldn't fit the batch would go * over the upper boundary and then it would have to be encoded again into a new * buffer. If the difference between the limit and the length of the buffer is * big enough (bigger than the biggest Netlink message) then this situation * won't occur. */ #define NL_DEFAULT_BATCH_SEND_THRESHOLD (15 * NL_PKT_BUF_SIZE) #define NL_BATCH_RX_BUFSIZE NL_RCV_PKT_BUF_SIZE static const struct message nlmsg_str[] = {{RTM_NEWROUTE, "RTM_NEWROUTE"}, {RTM_DELROUTE, "RTM_DELROUTE"}, {RTM_GETROUTE, "RTM_GETROUTE"}, {RTM_NEWLINK, "RTM_NEWLINK"}, {RTM_DELLINK, "RTM_DELLINK"}, {RTM_GETLINK, "RTM_GETLINK"}, {RTM_NEWADDR, "RTM_NEWADDR"}, {RTM_DELADDR, "RTM_DELADDR"}, {RTM_GETADDR, "RTM_GETADDR"}, {RTM_NEWNEIGH, "RTM_NEWNEIGH"}, {RTM_DELNEIGH, "RTM_DELNEIGH"}, {RTM_GETNEIGH, "RTM_GETNEIGH"}, {RTM_NEWRULE, "RTM_NEWRULE"}, {RTM_DELRULE, "RTM_DELRULE"}, {RTM_GETRULE, "RTM_GETRULE"}, {RTM_NEWNEXTHOP, "RTM_NEWNEXTHOP"}, {RTM_DELNEXTHOP, "RTM_DELNEXTHOP"}, {RTM_GETNEXTHOP, "RTM_GETNEXTHOP"}, {0}}; static const struct message rtproto_str[] = { {RTPROT_REDIRECT, "redirect"}, {RTPROT_KERNEL, "kernel"}, {RTPROT_BOOT, "boot"}, {RTPROT_STATIC, "static"}, {RTPROT_GATED, "GateD"}, {RTPROT_RA, "router advertisement"}, {RTPROT_MRT, "MRT"}, {RTPROT_ZEBRA, "Zebra"}, #ifdef RTPROT_BIRD {RTPROT_BIRD, "BIRD"}, #endif /* RTPROT_BIRD */ {RTPROT_MROUTED, "mroute"}, {RTPROT_BGP, "BGP"}, {RTPROT_OSPF, "OSPF"}, {RTPROT_ISIS, "IS-IS"}, {RTPROT_RIP, "RIP"}, {RTPROT_RIPNG, "RIPNG"}, {RTPROT_ZSTATIC, "static"}, {0}}; static const struct message family_str[] = {{AF_INET, "ipv4"}, {AF_INET6, "ipv6"}, {AF_BRIDGE, "bridge"}, {RTNL_FAMILY_IPMR, "ipv4MR"}, {RTNL_FAMILY_IP6MR, "ipv6MR"}, {0}}; static const struct message rttype_str[] = {{RTN_UNSPEC, "none"}, {RTN_UNICAST, "unicast"}, {RTN_LOCAL, "local"}, {RTN_BROADCAST, "broadcast"}, {RTN_ANYCAST, "anycast"}, {RTN_MULTICAST, "multicast"}, {RTN_BLACKHOLE, "blackhole"}, {RTN_UNREACHABLE, "unreachable"}, {RTN_PROHIBIT, "prohibited"}, {RTN_THROW, "throw"}, {RTN_NAT, "nat"}, {RTN_XRESOLVE, "resolver"}, {0}}; extern struct thread_master *master; extern uint32_t nl_rcvbufsize; extern struct zebra_privs_t zserv_privs; DEFINE_MTYPE_STATIC(ZEBRA, NL_BUF, "Zebra Netlink buffers") size_t nl_batch_tx_bufsize; char *nl_batch_tx_buf; char nl_batch_rx_buf[NL_BATCH_RX_BUFSIZE]; _Atomic uint32_t nl_batch_bufsize = NL_DEFAULT_BATCH_BUFSIZE; _Atomic uint32_t nl_batch_send_threshold = NL_DEFAULT_BATCH_SEND_THRESHOLD; struct nl_batch { void *buf; size_t bufsiz; size_t limit; void *buf_head; size_t curlen; size_t msgcnt; const struct zebra_dplane_info *zns; struct dplane_ctx_q ctx_list; /* * Pointer to the queue of completed contexts outbound back * towards the dataplane module. */ struct dplane_ctx_q *ctx_out_q; }; int netlink_config_write_helper(struct vty *vty) { uint32_t size = atomic_load_explicit(&nl_batch_bufsize, memory_order_relaxed); uint32_t threshold = atomic_load_explicit(&nl_batch_send_threshold, memory_order_relaxed); if (size != NL_DEFAULT_BATCH_BUFSIZE || threshold != NL_DEFAULT_BATCH_SEND_THRESHOLD) vty_out(vty, "zebra kernel netlink batch-tx-buf %u %u\n", size, threshold); return 0; } void netlink_set_batch_buffer_size(uint32_t size, uint32_t threshold, bool set) { if (!set) { size = NL_DEFAULT_BATCH_BUFSIZE; threshold = NL_DEFAULT_BATCH_SEND_THRESHOLD; } atomic_store_explicit(&nl_batch_bufsize, size, memory_order_relaxed); atomic_store_explicit(&nl_batch_send_threshold, threshold, memory_order_relaxed); } int netlink_talk_filter(struct nlmsghdr *h, ns_id_t ns_id, int startup) { /* * This is an error condition that must be handled during * development. * * The netlink_talk_filter function is used for communication * down the netlink_cmd pipe and we are expecting * an ack being received. So if we get here * then we did not receive the ack and instead * received some other message in an unexpected * way. */ zlog_debug("%s: ignoring message type 0x%04x(%s) NS %u", __func__, h->nlmsg_type, nl_msg_type_to_str(h->nlmsg_type), ns_id); return 0; } static int netlink_recvbuf(struct nlsock *nl, uint32_t newsize) { uint32_t oldsize; socklen_t newlen = sizeof(newsize); socklen_t oldlen = sizeof(oldsize); int ret; ret = getsockopt(nl->sock, SOL_SOCKET, SO_RCVBUF, &oldsize, &oldlen); if (ret < 0) { flog_err_sys(EC_LIB_SOCKET, "Can't get %s receive buffer size: %s", nl->name, safe_strerror(errno)); return -1; } /* Try force option (linux >= 2.6.14) and fall back to normal set */ frr_with_privs(&zserv_privs) { ret = setsockopt(nl->sock, SOL_SOCKET, SO_RCVBUFFORCE, &nl_rcvbufsize, sizeof(nl_rcvbufsize)); } if (ret < 0) ret = setsockopt(nl->sock, SOL_SOCKET, SO_RCVBUF, &nl_rcvbufsize, sizeof(nl_rcvbufsize)); if (ret < 0) { flog_err_sys(EC_LIB_SOCKET, "Can't set %s receive buffer size: %s", nl->name, safe_strerror(errno)); return -1; } ret = getsockopt(nl->sock, SOL_SOCKET, SO_RCVBUF, &newsize, &newlen); if (ret < 0) { flog_err_sys(EC_LIB_SOCKET, "Can't get %s receive buffer size: %s", nl->name, safe_strerror(errno)); return -1; } zlog_info("Setting netlink socket receive buffer size: %u -> %u", oldsize, newsize); return 0; } /* Make socket for Linux netlink interface. */ static int netlink_socket(struct nlsock *nl, unsigned long groups, ns_id_t ns_id) { int ret; struct sockaddr_nl snl; int sock; int namelen; frr_with_privs(&zserv_privs) { sock = ns_socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE, ns_id); if (sock < 0) { zlog_err("Can't open %s socket: %s", nl->name, safe_strerror(errno)); return -1; } memset(&snl, 0, sizeof(snl)); snl.nl_family = AF_NETLINK; snl.nl_groups = groups; /* Bind the socket to the netlink structure for anything. */ ret = bind(sock, (struct sockaddr *)&snl, sizeof(snl)); } if (ret < 0) { zlog_err("Can't bind %s socket to group 0x%x: %s", nl->name, snl.nl_groups, safe_strerror(errno)); close(sock); return -1; } /* multiple netlink sockets will have different nl_pid */ namelen = sizeof(snl); ret = getsockname(sock, (struct sockaddr *)&snl, (socklen_t *)&namelen); if (ret < 0 || namelen != sizeof(snl)) { flog_err_sys(EC_LIB_SOCKET, "Can't get %s socket name: %s", nl->name, safe_strerror(errno)); close(sock); return -1; } nl->snl = snl; nl->sock = sock; return ret; } static int netlink_information_fetch(struct nlmsghdr *h, ns_id_t ns_id, int startup) { /* * When we handle new message types here * because we are starting to install them * then lets check the netlink_install_filter * and see if we should add the corresponding * allow through entry there. * Probably not needed to do but please * think about it. */ switch (h->nlmsg_type) { case RTM_NEWROUTE: return netlink_route_change(h, ns_id, startup); case RTM_DELROUTE: return netlink_route_change(h, ns_id, startup); case RTM_NEWLINK: return netlink_link_change(h, ns_id, startup); case RTM_DELLINK: return netlink_link_change(h, ns_id, startup); case RTM_NEWADDR: return netlink_interface_addr(h, ns_id, startup); case RTM_DELADDR: return netlink_interface_addr(h, ns_id, startup); case RTM_NEWNEIGH: return netlink_neigh_change(h, ns_id); case RTM_DELNEIGH: return netlink_neigh_change(h, ns_id); case RTM_GETNEIGH: /* * Kernel in some situations when it expects * user space to resolve arp entries, we will * receive this notification. As we don't * need this notification and as that * we don't want to spam the log file with * below messages, just ignore. */ if (IS_ZEBRA_DEBUG_KERNEL) zlog_debug("Received RTM_GETNEIGH, ignoring"); break; case RTM_NEWRULE: return netlink_rule_change(h, ns_id, startup); case RTM_DELRULE: return netlink_rule_change(h, ns_id, startup); case RTM_NEWNEXTHOP: return netlink_nexthop_change(h, ns_id, startup); case RTM_DELNEXTHOP: return netlink_nexthop_change(h, ns_id, startup); default: /* * If we have received this message then * we have made a mistake during development * and we need to write some code to handle * this message type or not ask for * it to be sent up to us */ flog_err(EC_ZEBRA_UNKNOWN_NLMSG, "Unknown netlink nlmsg_type %s(%d) vrf %u", nl_msg_type_to_str(h->nlmsg_type), h->nlmsg_type, ns_id); break; } return 0; } static int kernel_read(struct thread *thread) { struct zebra_ns *zns = (struct zebra_ns *)THREAD_ARG(thread); struct zebra_dplane_info dp_info; /* Capture key info from ns struct */ zebra_dplane_info_from_zns(&dp_info, zns, false); netlink_parse_info(netlink_information_fetch, &zns->netlink, &dp_info, 5, 0); zns->t_netlink = NULL; thread_add_read(zrouter.master, kernel_read, zns, zns->netlink.sock, &zns->t_netlink); return 0; } /* * Filter out messages from self that occur on listener socket, * caused by our actions on the command socket(s) * * When we add new Netlink message types we probably * do not need to add them here as that we are filtering * on the routes we actually care to receive( which is rarer * then the normal course of operations). We are intentionally * allowing some messages from ourselves through * ( I'm looking at you Interface based netlink messages ) * so that we only had to write one way to handle incoming * address add/delete changes. */ static void netlink_install_filter(int sock, __u32 pid, __u32 dplane_pid) { /* * BPF_JUMP instructions and where you jump to are based upon * 0 as being the next statement. So count from 0. Writing * this down because every time I look at this I have to * re-remember it. */ struct sock_filter filter[] = { /* * Logic: * if (nlmsg_pid == pid || * nlmsg_pid == dplane_pid) { * if (the incoming nlmsg_type == * RTM_NEWADDR | RTM_DELADDR) * keep this message * else * skip this message * } else * keep this netlink message */ /* * 0: Load the nlmsg_pid into the BPF register */ BPF_STMT(BPF_LD | BPF_ABS | BPF_W, offsetof(struct nlmsghdr, nlmsg_pid)), /* * 1: Compare to pid */ BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, htonl(pid), 1, 0), /* * 2: Compare to dplane pid */ BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, htonl(dplane_pid), 0, 4), /* * 3: Load the nlmsg_type into BPF register */ BPF_STMT(BPF_LD | BPF_ABS | BPF_H, offsetof(struct nlmsghdr, nlmsg_type)), /* * 4: Compare to RTM_NEWADDR */ BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, htons(RTM_NEWADDR), 2, 0), /* * 5: Compare to RTM_DELADDR */ BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, htons(RTM_DELADDR), 1, 0), /* * 6: This is the end state of we want to skip the * message */ BPF_STMT(BPF_RET | BPF_K, 0), /* 7: This is the end state of we want to keep * the message */ BPF_STMT(BPF_RET | BPF_K, 0xffff), }; struct sock_fprog prog = { .len = array_size(filter), .filter = filter, }; if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER, &prog, sizeof(prog)) < 0) flog_err_sys(EC_LIB_SOCKET, "Can't install socket filter: %s", safe_strerror(errno)); } void netlink_parse_rtattr_flags(struct rtattr **tb, int max, struct rtattr *rta, int len, unsigned short flags) { unsigned short type; while (RTA_OK(rta, len)) { type = rta->rta_type & ~flags; if ((type <= max) && (!tb[type])) tb[type] = rta; rta = RTA_NEXT(rta, len); } } void netlink_parse_rtattr(struct rtattr **tb, int max, struct rtattr *rta, int len) { while (RTA_OK(rta, len)) { if (rta->rta_type <= max) tb[rta->rta_type] = rta; rta = RTA_NEXT(rta, len); } } /** * netlink_parse_rtattr_nested() - Parses a nested route attribute * @tb: Pointer to array for storing rtattr in. * @max: Max number to store. * @rta: Pointer to rtattr to look for nested items in. */ void netlink_parse_rtattr_nested(struct rtattr **tb, int max, struct rtattr *rta) { netlink_parse_rtattr(tb, max, RTA_DATA(rta), RTA_PAYLOAD(rta)); } bool nl_attr_put(struct nlmsghdr *n, unsigned int maxlen, int type, const void *data, unsigned int alen) { int len; struct rtattr *rta; len = RTA_LENGTH(alen); if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) return false; rta = (struct rtattr *)(((char *)n) + NLMSG_ALIGN(n->nlmsg_len)); rta->rta_type = type; rta->rta_len = len; if (data) memcpy(RTA_DATA(rta), data, alen); else assert(alen == 0); n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len); return true; } bool nl_attr_put16(struct nlmsghdr *n, unsigned int maxlen, int type, uint16_t data) { return nl_attr_put(n, maxlen, type, &data, sizeof(uint16_t)); } bool nl_attr_put32(struct nlmsghdr *n, unsigned int maxlen, int type, uint32_t data) { return nl_attr_put(n, maxlen, type, &data, sizeof(uint32_t)); } struct rtattr *nl_attr_nest(struct nlmsghdr *n, unsigned int maxlen, int type) { struct rtattr *nest = NLMSG_TAIL(n); if (!nl_attr_put(n, maxlen, type, NULL, 0)) return NULL; nest->rta_type |= NLA_F_NESTED; return nest; } int nl_attr_nest_end(struct nlmsghdr *n, struct rtattr *nest) { nest->rta_len = (uint8_t *)NLMSG_TAIL(n) - (uint8_t *)nest; return n->nlmsg_len; } struct rtnexthop *nl_attr_rtnh(struct nlmsghdr *n, unsigned int maxlen) { struct rtnexthop *rtnh = (struct rtnexthop *)NLMSG_TAIL(n); if (NLMSG_ALIGN(n->nlmsg_len) + RTNH_ALIGN(sizeof(struct rtnexthop)) > maxlen) return NULL; memset(rtnh, 0, sizeof(struct rtnexthop)); n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(sizeof(struct rtnexthop)); return rtnh; } void nl_attr_rtnh_end(struct nlmsghdr *n, struct rtnexthop *rtnh) { rtnh->rtnh_len = (uint8_t *)NLMSG_TAIL(n) - (uint8_t *)rtnh; } const char *nl_msg_type_to_str(uint16_t msg_type) { return lookup_msg(nlmsg_str, msg_type, ""); } const char *nl_rtproto_to_str(uint8_t rtproto) { return lookup_msg(rtproto_str, rtproto, ""); } const char *nl_family_to_str(uint8_t family) { return lookup_msg(family_str, family, ""); } const char *nl_rttype_to_str(uint8_t rttype) { return lookup_msg(rttype_str, rttype, ""); } #define NLA_OK(nla, len) \ ((len) >= (int)sizeof(struct nlattr) \ && (nla)->nla_len >= sizeof(struct nlattr) \ && (nla)->nla_len <= (len)) #define NLA_NEXT(nla, attrlen) \ ((attrlen) -= NLA_ALIGN((nla)->nla_len), \ (struct nlattr *)(((char *)(nla)) + NLA_ALIGN((nla)->nla_len))) #define NLA_LENGTH(len) (NLA_ALIGN(sizeof(struct nlattr)) + (len)) #define NLA_DATA(nla) ((struct nlattr *)(((char *)(nla)) + NLA_LENGTH(0))) #define ERR_NLA(err, inner_len) \ ((struct nlattr *)(((char *)(err)) \ + NLMSG_ALIGN(sizeof(struct nlmsgerr)) \ + NLMSG_ALIGN((inner_len)))) static void netlink_parse_nlattr(struct nlattr **tb, int max, struct nlattr *nla, int len) { while (NLA_OK(nla, len)) { if (nla->nla_type <= max) tb[nla->nla_type] = nla; nla = NLA_NEXT(nla, len); } } static void netlink_parse_extended_ack(struct nlmsghdr *h) { struct nlattr *tb[NLMSGERR_ATTR_MAX + 1] = {}; const struct nlmsgerr *err = (const struct nlmsgerr *)NLMSG_DATA(h); const struct nlmsghdr *err_nlh = NULL; /* Length not including nlmsghdr */ uint32_t len = 0; /* Inner error netlink message length */ uint32_t inner_len = 0; const char *msg = NULL; uint32_t off = 0; if (!(h->nlmsg_flags & NLM_F_CAPPED)) inner_len = (uint32_t)NLMSG_PAYLOAD(&err->msg, 0); len = (uint32_t)(NLMSG_PAYLOAD(h, sizeof(struct nlmsgerr)) - inner_len); netlink_parse_nlattr(tb, NLMSGERR_ATTR_MAX, ERR_NLA(err, inner_len), len); if (tb[NLMSGERR_ATTR_MSG]) msg = (const char *)NLA_DATA(tb[NLMSGERR_ATTR_MSG]); if (tb[NLMSGERR_ATTR_OFFS]) { off = *(uint32_t *)NLA_DATA(tb[NLMSGERR_ATTR_OFFS]); if (off > h->nlmsg_len) { zlog_err("Invalid offset for NLMSGERR_ATTR_OFFS"); } else if (!(h->nlmsg_flags & NLM_F_CAPPED)) { /* * Header of failed message * we are not doing anything currently with it * but noticing it for later. */ err_nlh = &err->msg; zlog_debug("%s: Received %s extended Ack", __func__, nl_msg_type_to_str(err_nlh->nlmsg_type)); } } if (msg && *msg != '\0') { bool is_err = !!err->error; if (is_err) zlog_err("Extended Error: %s", msg); else flog_warn(EC_ZEBRA_NETLINK_EXTENDED_WARNING, "Extended Warning: %s", msg); } } /* * netlink_send_msg - send a netlink message of a certain size. * * Returns -1 on error. Otherwise, it returns the number of bytes sent. */ static ssize_t netlink_send_msg(const struct nlsock *nl, void *buf, size_t buflen) { struct sockaddr_nl snl = {}; struct iovec iov = {}; struct msghdr msg = {}; ssize_t status; int save_errno = 0; iov.iov_base = buf; iov.iov_len = buflen; msg.msg_name = &snl; msg.msg_namelen = sizeof(snl); msg.msg_iov = &iov; msg.msg_iovlen = 1; snl.nl_family = AF_NETLINK; /* Send message to netlink interface. */ frr_with_privs(&zserv_privs) { status = sendmsg(nl->sock, &msg, 0); save_errno = errno; } if (IS_ZEBRA_DEBUG_KERNEL_MSGDUMP_SEND) { zlog_debug("%s: >> netlink message dump [sent]", __func__); #ifdef NETLINK_DEBUG nl_dump(buf, buflen); #else zlog_hexdump(buf, buflen); #endif /* NETLINK_DEBUG */ } if (status == -1) { flog_err_sys(EC_LIB_SOCKET, "%s error: %s", __func__, safe_strerror(save_errno)); return -1; } return status; } /* * netlink_recv_msg - receive a netlink message. * * Returns -1 on error, 0 if read would block or the number of bytes received. */ static int netlink_recv_msg(const struct nlsock *nl, struct msghdr msg, void *buf, size_t buflen) { struct iovec iov; int status; iov.iov_base = buf; iov.iov_len = buflen; msg.msg_iov = &iov; msg.msg_iovlen = 1; do { status = recvmsg(nl->sock, &msg, 0); } while (status == -1 && errno == EINTR); if (status == -1) { if (errno == EWOULDBLOCK || errno == EAGAIN) return 0; flog_err(EC_ZEBRA_RECVMSG_OVERRUN, "%s recvmsg overrun: %s", nl->name, safe_strerror(errno)); /* * In this case we are screwed. There is no good way to recover * zebra at this point. */ exit(-1); } if (status == 0) { flog_err_sys(EC_LIB_SOCKET, "%s EOF", nl->name); return -1; } if (msg.msg_namelen != sizeof(struct sockaddr_nl)) { flog_err(EC_ZEBRA_NETLINK_LENGTH_ERROR, "%s sender address length error: length %d", nl->name, msg.msg_namelen); return -1; } if (IS_ZEBRA_DEBUG_KERNEL_MSGDUMP_RECV) { zlog_debug("%s: << netlink message dump [recv]", __func__); #ifdef NETLINK_DEBUG nl_dump(buf, status); #else zlog_hexdump(buf, status); #endif /* NETLINK_DEBUG */ } return status; } /* * netlink_parse_error - parse a netlink error message * * Returns 1 if this message is acknowledgement, 0 if this error should be * ignored, -1 otherwise. */ static int netlink_parse_error(const struct nlsock *nl, struct nlmsghdr *h, const struct zebra_dplane_info *zns, bool startup) { struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h); int errnum = err->error; int msg_type = err->msg.nlmsg_type; if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) { flog_err(EC_ZEBRA_NETLINK_LENGTH_ERROR, "%s error: message truncated", nl->name); return -1; } /* * Parse the extended information before we actually handle it. At this * point in time we do not do anything other than report the issue. */ if (h->nlmsg_flags & NLM_F_ACK_TLVS) netlink_parse_extended_ack(h); /* If the error field is zero, then this is an ACK. */ if (err->error == 0) { if (IS_ZEBRA_DEBUG_KERNEL) { zlog_debug("%s: %s ACK: type=%s(%u), seq=%u, pid=%u", __func__, nl->name, nl_msg_type_to_str(err->msg.nlmsg_type), err->msg.nlmsg_type, err->msg.nlmsg_seq, err->msg.nlmsg_pid); } return 1; } /* Deal with errors that occur because of races in link handling. */ if (zns->is_cmd && ((msg_type == RTM_DELROUTE && (-errnum == ENODEV || -errnum == ESRCH)) || (msg_type == RTM_NEWROUTE && (-errnum == ENETDOWN || -errnum == EEXIST)))) { if (IS_ZEBRA_DEBUG_KERNEL) zlog_debug("%s: error: %s type=%s(%u), seq=%u, pid=%u", nl->name, safe_strerror(-errnum), nl_msg_type_to_str(msg_type), msg_type, err->msg.nlmsg_seq, err->msg.nlmsg_pid); return 0; } /* * We see RTM_DELNEIGH when shutting down an interface with an IPv4 * link-local. The kernel should have already deleted the neighbor so * do not log these as an error. */ if (msg_type == RTM_DELNEIGH || (zns->is_cmd && msg_type == RTM_NEWROUTE && (-errnum == ESRCH || -errnum == ENETUNREACH))) { /* * This is known to happen in some situations, don't log as * error. */ if (IS_ZEBRA_DEBUG_KERNEL) zlog_debug("%s error: %s, type=%s(%u), seq=%u, pid=%u", nl->name, safe_strerror(-errnum), nl_msg_type_to_str(msg_type), msg_type, err->msg.nlmsg_seq, err->msg.nlmsg_pid); } else { if ((msg_type != RTM_GETNEXTHOP) || !startup) flog_err(EC_ZEBRA_UNEXPECTED_MESSAGE, "%s error: %s, type=%s(%u), seq=%u, pid=%u", nl->name, safe_strerror(-errnum), nl_msg_type_to_str(msg_type), msg_type, err->msg.nlmsg_seq, err->msg.nlmsg_pid); } return -1; } /* * netlink_parse_info * * Receive message from netlink interface and pass those information * to the given function. * * filter -> Function to call to read the results * nl -> netlink socket information * zns -> The zebra namespace data * count -> How many we should read in, 0 means as much as possible * startup -> Are we reading in under startup conditions? passed to * the filter. */ int netlink_parse_info(int (*filter)(struct nlmsghdr *, ns_id_t, int), const struct nlsock *nl, const struct zebra_dplane_info *zns, int count, int startup) { int status; int ret = 0; int error; int read_in = 0; while (1) { char buf[NL_RCV_PKT_BUF_SIZE]; struct sockaddr_nl snl; struct msghdr msg = {.msg_name = (void *)&snl, .msg_namelen = sizeof(snl)}; struct nlmsghdr *h; if (count && read_in >= count) return 0; status = netlink_recv_msg(nl, msg, buf, sizeof(buf)); if (status == -1) return -1; else if (status == 0) break; read_in++; for (h = (struct nlmsghdr *)buf; (status >= 0 && NLMSG_OK(h, (unsigned int)status)); h = NLMSG_NEXT(h, status)) { /* Finish of reading. */ if (h->nlmsg_type == NLMSG_DONE) return ret; /* Error handling. */ if (h->nlmsg_type == NLMSG_ERROR) { int err = netlink_parse_error(nl, h, zns, startup); if (err == 1) { if (!(h->nlmsg_flags & NLM_F_MULTI)) return 0; continue; } else return err; } /* OK we got netlink message. */ if (IS_ZEBRA_DEBUG_KERNEL) zlog_debug( "netlink_parse_info: %s type %s(%u), len=%d, seq=%u, pid=%u", nl->name, nl_msg_type_to_str(h->nlmsg_type), h->nlmsg_type, h->nlmsg_len, h->nlmsg_seq, h->nlmsg_pid); /* * Ignore messages that maybe sent from * other actors besides the kernel */ if (snl.nl_pid != 0) { zlog_debug("Ignoring message from pid %u", snl.nl_pid); continue; } error = (*filter)(h, zns->ns_id, startup); if (error < 0) { zlog_debug("%s filter function error", nl->name); ret = error; } } /* After error care. */ if (msg.msg_flags & MSG_TRUNC) { flog_err(EC_ZEBRA_NETLINK_LENGTH_ERROR, "%s error: message truncated", nl->name); continue; } if (status) { flog_err(EC_ZEBRA_NETLINK_LENGTH_ERROR, "%s error: data remnant size %d", nl->name, status); return -1; } } return ret; } /* * netlink_talk_info * * sendmsg() to netlink socket then recvmsg(). * Calls netlink_parse_info to parse returned data * * filter -> The filter to read final results from kernel * nlmsghdr -> The data to send to the kernel * dp_info -> The dataplane and netlink socket information * startup -> Are we reading in under startup conditions * This is passed through eventually to filter. */ static int netlink_talk_info(int (*filter)(struct nlmsghdr *, ns_id_t, int startup), struct nlmsghdr *n, const struct zebra_dplane_info *dp_info, int startup) { const struct nlsock *nl; nl = &(dp_info->nls); n->nlmsg_seq = nl->seq; n->nlmsg_pid = nl->snl.nl_pid; if (IS_ZEBRA_DEBUG_KERNEL) zlog_debug( "netlink_talk: %s type %s(%u), len=%d seq=%u flags 0x%x", nl->name, nl_msg_type_to_str(n->nlmsg_type), n->nlmsg_type, n->nlmsg_len, n->nlmsg_seq, n->nlmsg_flags); if (netlink_send_msg(nl, n, n->nlmsg_len) == -1) return -1; /* * Get reply from netlink socket. * The reply should either be an acknowlegement or an error. */ return netlink_parse_info(filter, nl, dp_info, 0, startup); } /* * Synchronous version of netlink_talk_info. Converts args to suit the * common version, which is suitable for both sync and async use. */ int netlink_talk(int (*filter)(struct nlmsghdr *, ns_id_t, int startup), struct nlmsghdr *n, struct nlsock *nl, struct zebra_ns *zns, int startup) { struct zebra_dplane_info dp_info; /* Increment sequence number before capturing snapshot of ns socket * info. */ nl->seq++; /* Capture info in intermediate info struct */ zebra_dplane_info_from_zns(&dp_info, zns, (nl == &(zns->netlink_cmd))); return netlink_talk_info(filter, n, &dp_info, startup); } /* Issue request message to kernel via netlink socket. GET messages * are issued through this interface. */ int netlink_request(struct nlsock *nl, void *req) { struct nlmsghdr *n = (struct nlmsghdr *)req; /* Check netlink socket. */ if (nl->sock < 0) { flog_err_sys(EC_LIB_SOCKET, "%s socket isn't active.", nl->name); return -1; } /* Fill common fields for all requests. */ n->nlmsg_pid = nl->snl.nl_pid; n->nlmsg_seq = ++nl->seq; if (netlink_send_msg(nl, req, n->nlmsg_len) == -1) return -1; return 0; } static int nl_batch_read_resp(struct nl_batch *bth) { struct nlmsghdr *h; struct sockaddr_nl snl; struct msghdr msg = {}; int status, seq; const struct nlsock *nl; struct zebra_dplane_ctx *ctx; bool ignore_msg; nl = &(bth->zns->nls); msg.msg_name = (void *)&snl; msg.msg_namelen = sizeof(snl); /* * The responses are not batched, so we need to read and process one * message at a time. */ while (true) { status = netlink_recv_msg(nl, msg, nl_batch_rx_buf, sizeof(nl_batch_rx_buf)); if (status == -1 || status == 0) return status; h = (struct nlmsghdr *)nl_batch_rx_buf; ignore_msg = false; seq = h->nlmsg_seq; /* * Find the corresponding context object. Received responses are * in the same order as requests we sent, so we can simply * iterate over the context list and match responses with * requests at same time. */ while (true) { ctx = dplane_ctx_dequeue(&(bth->ctx_list)); if (ctx == NULL) break; dplane_ctx_enqueue_tail(bth->ctx_out_q, ctx); /* We have found corresponding context object. */ if (dplane_ctx_get_ns(ctx)->nls.seq == seq) break; /* * 'update' context objects take two consecutive * sequence numbers. */ if (dplane_ctx_is_update(ctx) && dplane_ctx_get_ns(ctx)->nls.seq + 1 == seq) { /* * This is the situation where we get a response * to a message that should be ignored. */ ignore_msg = true; break; } } if (ignore_msg) continue; /* * We received a message with the sequence number that isn't * associated with any dplane context object. */ if (ctx == NULL) { if (IS_ZEBRA_DEBUG_KERNEL) zlog_debug( "%s: skipping unassociated response, seq number %d NS %u", __func__, h->nlmsg_seq, bth->zns->ns_id); continue; } if (h->nlmsg_type == NLMSG_ERROR) { int err = netlink_parse_error(nl, h, bth->zns, 0); if (err == -1) dplane_ctx_set_status( ctx, ZEBRA_DPLANE_REQUEST_FAILURE); if (IS_ZEBRA_DEBUG_KERNEL) zlog_debug("%s: netlink error message seq=%d ", __func__, h->nlmsg_seq); continue; } /* * If we get here then we did not receive neither the ack nor * the error and instead received some other message in an * unexpected way. */ if (IS_ZEBRA_DEBUG_KERNEL) zlog_debug("%s: ignoring message type 0x%04x(%s) NS %u", __func__, h->nlmsg_type, nl_msg_type_to_str(h->nlmsg_type), bth->zns->ns_id); } return 0; } static void nl_batch_reset(struct nl_batch *bth) { bth->buf_head = bth->buf; bth->curlen = 0; bth->msgcnt = 0; bth->zns = NULL; TAILQ_INIT(&(bth->ctx_list)); } static void nl_batch_init(struct nl_batch *bth, struct dplane_ctx_q *ctx_out_q) { /* * If the size of the buffer has changed, free and then allocate a new * one. */ size_t bufsize = atomic_load_explicit(&nl_batch_bufsize, memory_order_relaxed); if (bufsize != nl_batch_tx_bufsize) { if (nl_batch_tx_buf) XFREE(MTYPE_NL_BUF, nl_batch_tx_buf); nl_batch_tx_buf = XCALLOC(MTYPE_NL_BUF, bufsize); nl_batch_tx_bufsize = bufsize; } bth->buf = nl_batch_tx_buf; bth->bufsiz = bufsize; bth->limit = atomic_load_explicit(&nl_batch_send_threshold, memory_order_relaxed); bth->ctx_out_q = ctx_out_q; nl_batch_reset(bth); } static void nl_batch_send(struct nl_batch *bth) { struct zebra_dplane_ctx *ctx; bool err = false; if (bth->curlen != 0 && bth->zns != NULL) { if (IS_ZEBRA_DEBUG_KERNEL) zlog_debug("%s: %s, batch size=%zu, msg cnt=%zu", __func__, bth->zns->nls.name, bth->curlen, bth->msgcnt); if (netlink_send_msg(&(bth->zns->nls), bth->buf, bth->curlen) == -1) err = true; if (!err) { if (nl_batch_read_resp(bth) == -1) err = true; } } /* Move remaining contexts to the outbound queue. */ while (true) { ctx = dplane_ctx_dequeue(&(bth->ctx_list)); if (ctx == NULL) break; if (err) dplane_ctx_set_status(ctx, ZEBRA_DPLANE_REQUEST_FAILURE); dplane_ctx_enqueue_tail(bth->ctx_out_q, ctx); } nl_batch_reset(bth); } enum netlink_msg_status netlink_batch_add_msg( struct nl_batch *bth, struct zebra_dplane_ctx *ctx, ssize_t (*msg_encoder)(struct zebra_dplane_ctx *, void *, size_t), bool ignore_res) { int seq; ssize_t size; struct nlmsghdr *msgh; size = (*msg_encoder)(ctx, bth->buf_head, bth->bufsiz - bth->curlen); /* * If there was an error while encoding the message (other than buffer * overflow) then return an error. */ if (size < 0) return FRR_NETLINK_ERROR; /* * If the message doesn't fit entirely in the buffer then send the batch * and retry. */ if (size == 0) { nl_batch_send(bth); size = (*msg_encoder)(ctx, bth->buf_head, bth->bufsiz - bth->curlen); /* * If the message doesn't fit in the empty buffer then just * return an error. */ if (size <= 0) return FRR_NETLINK_ERROR; } seq = dplane_ctx_get_ns(ctx)->nls.seq; if (ignore_res) seq++; msgh = (struct nlmsghdr *)bth->buf_head; msgh->nlmsg_seq = seq; msgh->nlmsg_pid = dplane_ctx_get_ns(ctx)->nls.snl.nl_pid; bth->zns = dplane_ctx_get_ns(ctx); bth->buf_head = ((char *)bth->buf_head) + size; bth->curlen += size; bth->msgcnt++; return FRR_NETLINK_QUEUED; } static enum netlink_msg_status nl_put_msg(struct nl_batch *bth, struct zebra_dplane_ctx *ctx) { if (dplane_ctx_is_skip_kernel(ctx)) return FRR_NETLINK_SUCCESS; switch (dplane_ctx_get_op(ctx)) { case DPLANE_OP_ROUTE_INSTALL: case DPLANE_OP_ROUTE_UPDATE: case DPLANE_OP_ROUTE_DELETE: return netlink_put_route_update_msg(bth, ctx); case DPLANE_OP_NH_INSTALL: case DPLANE_OP_NH_UPDATE: case DPLANE_OP_NH_DELETE: return netlink_put_nexthop_update_msg(bth, ctx); case DPLANE_OP_LSP_INSTALL: case DPLANE_OP_LSP_UPDATE: case DPLANE_OP_LSP_DELETE: return netlink_put_lsp_update_msg(bth, ctx); case DPLANE_OP_PW_INSTALL: case DPLANE_OP_PW_UNINSTALL: return netlink_put_pw_update_msg(bth, ctx); case DPLANE_OP_ADDR_INSTALL: case DPLANE_OP_ADDR_UNINSTALL: return netlink_put_address_update_msg(bth, ctx); case DPLANE_OP_MAC_INSTALL: case DPLANE_OP_MAC_DELETE: return netlink_put_mac_update_msg(bth, ctx); case DPLANE_OP_NEIGH_INSTALL: case DPLANE_OP_NEIGH_UPDATE: case DPLANE_OP_NEIGH_DELETE: case DPLANE_OP_VTEP_ADD: case DPLANE_OP_VTEP_DELETE: case DPLANE_OP_NEIGH_DISCOVER: return netlink_put_neigh_update_msg(bth, ctx); case DPLANE_OP_RULE_ADD: case DPLANE_OP_RULE_DELETE: case DPLANE_OP_RULE_UPDATE: return netlink_put_rule_update_msg(bth, ctx); case DPLANE_OP_SYS_ROUTE_ADD: case DPLANE_OP_SYS_ROUTE_DELETE: case DPLANE_OP_ROUTE_NOTIFY: case DPLANE_OP_LSP_NOTIFY: case DPLANE_OP_BR_PORT_UPDATE: return FRR_NETLINK_SUCCESS; case DPLANE_OP_NONE: return FRR_NETLINK_ERROR; } return FRR_NETLINK_ERROR; } void kernel_update_multi(struct dplane_ctx_q *ctx_list) { struct nl_batch batch; struct zebra_dplane_ctx *ctx; struct dplane_ctx_q handled_list; enum netlink_msg_status res; TAILQ_INIT(&handled_list); nl_batch_init(&batch, &handled_list); while (true) { ctx = dplane_ctx_dequeue(ctx_list); if (ctx == NULL) break; if (batch.zns != NULL && batch.zns->ns_id != dplane_ctx_get_ns(ctx)->ns_id) nl_batch_send(&batch); /* * Assume all messages will succeed and then mark only the ones * that failed. */ dplane_ctx_set_status(ctx, ZEBRA_DPLANE_REQUEST_SUCCESS); res = nl_put_msg(&batch, ctx); dplane_ctx_enqueue_tail(&(batch.ctx_list), ctx); if (res == FRR_NETLINK_ERROR) dplane_ctx_set_status(ctx, ZEBRA_DPLANE_REQUEST_FAILURE); if (batch.curlen > batch.limit) nl_batch_send(&batch); } nl_batch_send(&batch); TAILQ_INIT(ctx_list); dplane_ctx_list_append(ctx_list, &handled_list); } /* Exported interface function. This function simply calls netlink_socket (). */ void kernel_init(struct zebra_ns *zns) { uint32_t groups; #if defined SOL_NETLINK int one, ret; #endif /* * Initialize netlink sockets * * If RTMGRP_XXX exists use that, but at some point * I think the kernel developers realized that * keeping track of all the different values would * lead to confusion, so we need to convert the * RTNLGRP_XXX to a bit position for ourself */ groups = RTMGRP_LINK | RTMGRP_IPV4_ROUTE | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_ROUTE | RTMGRP_IPV6_IFADDR | RTMGRP_IPV4_MROUTE | RTMGRP_NEIGH | ((uint32_t) 1 << (RTNLGRP_IPV4_RULE - 1)) | ((uint32_t) 1 << (RTNLGRP_IPV6_RULE - 1)) | ((uint32_t) 1 << (RTNLGRP_NEXTHOP - 1)); snprintf(zns->netlink.name, sizeof(zns->netlink.name), "netlink-listen (NS %u)", zns->ns_id); zns->netlink.sock = -1; if (netlink_socket(&zns->netlink, groups, zns->ns_id) < 0) { zlog_err("Failure to create %s socket", zns->netlink.name); exit(-1); } snprintf(zns->netlink_cmd.name, sizeof(zns->netlink_cmd.name), "netlink-cmd (NS %u)", zns->ns_id); zns->netlink_cmd.sock = -1; if (netlink_socket(&zns->netlink_cmd, 0, zns->ns_id) < 0) { zlog_err("Failure to create %s socket", zns->netlink_cmd.name); exit(-1); } snprintf(zns->netlink_dplane.name, sizeof(zns->netlink_dplane.name), "netlink-dp (NS %u)", zns->ns_id); zns->netlink_dplane.sock = -1; if (netlink_socket(&zns->netlink_dplane, 0, zns->ns_id) < 0) { zlog_err("Failure to create %s socket", zns->netlink_dplane.name); exit(-1); } /* * SOL_NETLINK is not available on all platforms yet * apparently. It's in bits/socket.h which I am not * sure that we want to pull into our build system. */ #if defined SOL_NETLINK /* * Let's tell the kernel that we want to receive extended * ACKS over our command socket(s) */ one = 1; ret = setsockopt(zns->netlink_cmd.sock, SOL_NETLINK, NETLINK_EXT_ACK, &one, sizeof(one)); if (ret < 0) zlog_notice("Registration for extended cmd ACK failed : %d %s", errno, safe_strerror(errno)); one = 1; ret = setsockopt(zns->netlink_dplane.sock, SOL_NETLINK, NETLINK_EXT_ACK, &one, sizeof(one)); if (ret < 0) zlog_notice("Registration for extended dp ACK failed : %d %s", errno, safe_strerror(errno)); /* * Trim off the payload of the original netlink message in the * acknowledgment. This option is available since Linux 4.2, so if * setsockopt fails, ignore the error. */ one = 1; ret = setsockopt(zns->netlink_dplane.sock, SOL_NETLINK, NETLINK_CAP_ACK, &one, sizeof(one)); if (ret < 0) zlog_notice( "Registration for reduced ACK packet size failed, probably running an early kernel"); #endif /* Register kernel socket. */ if (fcntl(zns->netlink.sock, F_SETFL, O_NONBLOCK) < 0) flog_err_sys(EC_LIB_SOCKET, "Can't set %s socket flags: %s", zns->netlink.name, safe_strerror(errno)); if (fcntl(zns->netlink_cmd.sock, F_SETFL, O_NONBLOCK) < 0) zlog_err("Can't set %s socket error: %s(%d)", zns->netlink_cmd.name, safe_strerror(errno), errno); if (fcntl(zns->netlink_dplane.sock, F_SETFL, O_NONBLOCK) < 0) zlog_err("Can't set %s socket error: %s(%d)", zns->netlink_dplane.name, safe_strerror(errno), errno); /* Set receive buffer size if it's set from command line */ if (nl_rcvbufsize) { netlink_recvbuf(&zns->netlink, nl_rcvbufsize); netlink_recvbuf(&zns->netlink_cmd, nl_rcvbufsize); netlink_recvbuf(&zns->netlink_dplane, nl_rcvbufsize); } netlink_install_filter(zns->netlink.sock, zns->netlink_cmd.snl.nl_pid, zns->netlink_dplane.snl.nl_pid); zns->t_netlink = NULL; thread_add_read(zrouter.master, kernel_read, zns, zns->netlink.sock, &zns->t_netlink); rt_netlink_init(); } void kernel_terminate(struct zebra_ns *zns, bool complete) { thread_cancel(&zns->t_netlink); if (zns->netlink.sock >= 0) { close(zns->netlink.sock); zns->netlink.sock = -1; } if (zns->netlink_cmd.sock >= 0) { close(zns->netlink_cmd.sock); zns->netlink_cmd.sock = -1; } /* During zebra shutdown, we need to leave the dataplane socket * around until all work is done. */ if (complete) { if (zns->netlink_dplane.sock >= 0) { close(zns->netlink_dplane.sock); zns->netlink_dplane.sock = -1; } } } #endif /* HAVE_NETLINK */