diff options
| -rw-r--r-- | TODO | 4 | ||||
| -rw-r--r-- | sysdep/linux/netlink/krt.c | 249 |
2 files changed, 249 insertions, 4 deletions
@@ -21,8 +21,7 @@ Core - broadcast/multicast echoing suppresion - we need ifindex at least for PtP links -- kernel: RTM_F_NOTIFY seems to be unimplemented -- kernel: RTM_DELROUTE not announced for device routes +- kernel: RTM_DELROUTE not announced for device routes [confirmed by Alexey: it's a feature] - netlink: import Linux route attributes to our rta's, so that they can be filtered? @@ -35,6 +34,7 @@ Cleanup - check log calls for trailing newlines - check if all protocols set proper packet priorities and TTL's. - replace all NUM's by expr's +- try compiling with -Wunused Various ideas ~~~~~~~~~~~~~ diff --git a/sysdep/linux/netlink/krt.c b/sysdep/linux/netlink/krt.c index aae8918..3dde7be 100644 --- a/sysdep/linux/netlink/krt.c +++ b/sysdep/linux/netlink/krt.c @@ -10,6 +10,11 @@ #include <stdio.h> #include <fcntl.h> #include <sys/socket.h> +#include <sys/uio.h> + +#define LOCAL_DEBUG + +#undef ASYNC_NETLINK /* Define if async notifications should be used (debug) */ #include "nest/bird.h" #include "nest/route.h" @@ -18,6 +23,7 @@ #include "lib/timer.h" #include "lib/unix.h" #include "lib/krt.h" +#include "lib/socket.h" /* * We need to work around namespace conflicts between us and the kernel, @@ -35,10 +41,218 @@ #include <linux/netlink.h> #include <linux/rtnetlink.h> -#define LOCAL_DEBUG +#ifndef MSG_TRUNC /* FIXME: Hack to circumvent omissions in glibc includes */ +#define MSG_TRUNC 0x20 +#endif struct proto_config *cf_krt; +/* + * Synchronous Netlink interface + */ + +static int nl_sync_fd; /* Unix socket for synchronous netlink actions */ +static u32 nl_sync_seq; /* Sequence number of last request sent */ + +static byte *nl_rx_buffer; /* Receive buffer */ +static int nl_rx_size = 8192; + +static struct nlmsghdr *nl_last_hdr; /* Recently received packet */ +static unsigned int nl_last_size; + +static void +nl_send(void *rq, int size) +{ + struct nlmsghdr *nh = rq; + struct sockaddr_nl sa; + + memset(&sa, 0, sizeof(sa)); + sa.nl_family = AF_NETLINK; + nh->nlmsg_len = size; + nh->nlmsg_pid = 0; + nh->nlmsg_seq = ++nl_sync_seq; + if (sendto(nl_sync_fd, rq, size, 0, (struct sockaddr *)&sa, sizeof(sa)) < 0) + die("rtnetlink sendto: %m"); + nl_last_hdr = NULL; +} + +static void +nl_request_dump(int cmd) +{ + struct { + struct nlmsghdr nh; + struct rtgenmsg g; + } req; + req.nh.nlmsg_type = cmd; + req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP; + req.g.rtgen_family = PF_INET; + nl_send(&req, sizeof(req)); +} + +static struct nlmsghdr * +nl_get_reply(void) +{ + for(;;) + { + if (!nl_last_hdr) + { + struct iovec iov = { nl_rx_buffer, nl_rx_size }; + struct sockaddr_nl sa; + struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 }; + int x = recvmsg(nl_sync_fd, &m, 0); + if (x < 0) + die("nl_get_reply: %m"); + nl_last_size = x; + nl_last_hdr = (void *) nl_rx_buffer; + if (m.msg_flags & MSG_TRUNC) + bug("nl_get_reply: got truncated reply which should be impossible"); + } + if (NLMSG_OK(nl_last_hdr, nl_last_size)) + { + struct nlmsghdr *h = nl_last_hdr; + if (h->nlmsg_seq != nl_sync_seq) + { + log(L_WARN "nl_get_reply: Ignoring out of sequence netlink packet (%x != %x)", + h->nlmsg_seq, nl_sync_seq); + continue; + } + nl_last_hdr = NLMSG_NEXT(h, nl_last_size); + return h; + } + if (nl_last_size) + log(L_WARN "nl_get_reply: Found packet remnant of size %d", nl_last_size); + nl_last_hdr = NULL; + } +} + +static char * +nl_error(struct nlmsghdr *h) +{ + struct nlmsgerr *e = NLMSG_DATA(h); + if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) + return "Error message truncated"; + else + return strerror(-e->error); +} + +static struct nlmsghdr * +nl_get_scan(void) +{ + struct nlmsghdr *h = nl_get_reply(); + + if (h->nlmsg_type == NLMSG_DONE) + return NULL; + if (h->nlmsg_type == NLMSG_ERROR) + { + log(L_ERR "Netlink error: %s", nl_error(h)); + return NULL; + } + return h; +} + +/* + * Parsing of Netlink attributes + */ + +static int nl_attr_len; + +static void * +nl_checkin(struct nlmsghdr *h, int lsize) +{ + nl_attr_len = h->nlmsg_len - NLMSG_LENGTH(lsize); + if (nl_attr_len < 0) + { + log(L_ERR "nl_checkin: underrun by %d bytes", -nl_attr_len); + return NULL; + } + return NLMSG_DATA(h); +} + +static int +nl_parse_attrs(struct rtattr *a, struct rtattr **k, int ksize) +{ + int max = ksize / sizeof(struct rtattr *); + bzero(k, ksize); + while (RTA_OK(a, nl_attr_len)) + { + if (a->rta_type < max) + k[a->rta_type] = a; + a = RTA_NEXT(a, nl_attr_len); + } + if (nl_attr_len) + { + log(L_ERR "nl_parse_attrs: remnant of size %d", nl_attr_len); + return 0; + } + else + return 1; +} + +/* + * Scanning of interfaces + */ + +static void +nl_parse_link(struct nlmsghdr *h) +{ + struct ifinfomsg *i; + struct rtattr *a[IFLA_STATS+1]; + + if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFLA_RTA(i), a, sizeof(a))) + return; + DBG("NEWLINK %d\n", i->ifi_index); +} + +static void +nl_parse_addr(struct nlmsghdr *h) +{ + struct ifaddrmsg *i; + struct rtattr *a[IFA_ANYCAST+1]; + + if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFA_RTA(i), a, sizeof(a))) + return; + DBG("NEWADDR %d\n", i->ifa_index); +} + +static void +nl_scan_ifaces(void) +{ + struct nlmsghdr *h; + + nl_request_dump(RTM_GETLINK); + while (h = nl_get_scan()) + if (h->nlmsg_type == RTM_NEWLINK || h->nlmsg_type == RTM_DELLINK) + nl_parse_link(h); + else + log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type); + + nl_request_dump(RTM_GETADDR); + while (h = nl_get_scan()) + if (h->nlmsg_type == RTM_NEWADDR || h->nlmsg_type == RTM_DELADDR) + nl_parse_addr(h); + else + log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type); + + bug("NIIDW"); +} + +/* + * Asynchronous Netlink interface + */ + +static sock *nl_async_sk; /* BIRD socket for asynchronous notifications */ + +static int +nl_async_hook(sock *sk, int size) +{ + DBG("nl_async_hook\n"); + return 0; +} + +/* + * Protocol core + */ + static void krt_preconfig(struct protocol *x, struct config *c) { @@ -56,9 +270,33 @@ krt_init(struct proto_config *c) return &p->p; } +static void +nl_open_async(struct proto *p) +{ + sock *sk; + struct sockaddr_nl sa; + + sk = nl_async_sk = sk_new(p->pool); + sk->type = SK_MAGIC; + sk->rx_hook = nl_async_hook; + sk->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE); + if (sk->fd < 0 || sk_open(sk)) + die("Unable to open secondary rtnetlink socket: %m"); + + bzero(&sa, sizeof(sa)); + sa.nl_family = AF_NETLINK; + sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE; + if (bind(sk->fd, (struct sockaddr *) &sa, sizeof(sa)) < 0) + die("Unable to bind secondary rtnetlink socket: %m"); +} + static int krt_start(struct proto *p) { +#ifdef ASYNC_NETLINK + nl_open_async(p); +#endif + /* FIXME: Filter kernel routing table etc. */ return PS_UP; @@ -75,7 +313,14 @@ krt_shutdown(struct proto *p) void scan_if_init(void) { - /* FIXME: What to do here? */ + nl_sync_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE); + if (nl_sync_fd < 0) + die("Unable to open rtnetlink socket: %m"); + nl_sync_seq = now; + nl_rx_buffer = xmalloc(nl_rx_size); + /* FIXME: Should we fetch our local address and compare it with addresses of all incoming messages? */ + + nl_scan_ifaces(); } struct protocol proto_unix_kernel = { |