KRT: Implemented asynchronous route / interface state notifications
(via Netlink). Tweaked kernel synchronization rules a bit. Discovered locking bug in kernel Netlink :-) Future plans: Hunt all the bugs and solve all the FIXME's.
This commit is contained in:
Martin Mares
parent
2253c9e239
commit
e16155ae4a
6 changed files with 178 additions and 18 deletions
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@ -140,6 +140,9 @@ typedef struct rte {
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struct {
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} bgp;
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#endif
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struct { /* Routes internally generated by krt sync */
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int src; /* Alleged route source (see krt.h) */
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} krt_sync;
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} u;
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} rte;
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@ -127,6 +127,7 @@ krt_parse_entry(byte *ent, struct krt_proto *p)
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e = rte_get_temp(&a);
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e->net = net;
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e->u.krt_sync.src = KRT_SRC_UNKNOWN;
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krt_got_route(p, e);
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}
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@ -57,7 +57,7 @@ static int nl_sync_fd = -1; /* Unix socket for synchronous netlink actions */
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static u32 nl_sync_seq; /* Sequence number of last request sent */
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static byte *nl_rx_buffer; /* Receive buffer */
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static int nl_rx_size = 8192;
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#define NL_RX_SIZE 2048
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static struct nlmsghdr *nl_last_hdr; /* Recently received packet */
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static unsigned int nl_last_size;
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@ -71,7 +71,7 @@ nl_open(void)
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if (nl_sync_fd < 0)
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die("Unable to open rtnetlink socket: %m");
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nl_sync_seq = now;
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nl_rx_buffer = xmalloc(nl_rx_size);
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nl_rx_buffer = xmalloc(NL_RX_SIZE);
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}
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}
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@ -110,7 +110,7 @@ nl_get_reply(void)
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{
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if (!nl_last_hdr)
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{
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struct iovec iov = { nl_rx_buffer, nl_rx_size };
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struct iovec iov = { nl_rx_buffer, NL_RX_SIZE };
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struct sockaddr_nl sa;
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struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
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int x = recvmsg(nl_sync_fd, &m, 0);
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@ -456,6 +456,8 @@ nl_send_route(rte *e, int new)
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} r;
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struct nlmsghdr *reply;
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DBG("nl_send_route(%I/%d,new=%d)\n", net->n.prefix, net->n.pxlen, new);
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bzero(&r.h, sizeof(r.h));
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bzero(&r.r, sizeof(r.r));
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r.h.nlmsg_type = new ? RTM_NEWROUTE : RTM_DELROUTE;
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@ -499,6 +501,10 @@ nl_send_route(rte *e, int new)
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void
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krt_set_notify(struct proto *p, net *n, rte *new, rte *old)
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{
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if (old && old->attrs->source == RTS_DEVICE) /* Device routes are left to the kernel */
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old = NULL;
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if (new && new->attrs->source == RTS_DEVICE)
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new = NULL;
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if (old && new && old->attrs->tos == new->attrs->tos)
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{
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/* FIXME: Priorities should be identical as well, but we don't use them yet. */
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@ -507,7 +513,11 @@ krt_set_notify(struct proto *p, net *n, rte *new, rte *old)
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else
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{
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if (old)
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nl_send_route(old, 0);
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{
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if (!old->attrs->iface || (old->attrs->iface->flags & IF_UP))
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nl_send_route(old, 0);
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/* else the kernel has already flushed it */
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}
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if (new)
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nl_send_route(new, 1);
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}
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@ -542,6 +552,7 @@ nl_parse_route(struct krt_proto *p, struct nlmsghdr *h, int scan)
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rte *e;
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net *net;
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u32 oif;
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int src;
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if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(RTM_RTA(i), a, sizeof(a)))
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return;
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@ -559,7 +570,8 @@ nl_parse_route(struct krt_proto *p, struct nlmsghdr *h, int scan)
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return;
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if (i->rtm_tos != 0) /* FIXME: What about TOS? */
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return;
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if (!new)
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if (scan && !new)
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{
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DBG("KRT: Ignoring route deletion\n");
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return;
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@ -579,6 +591,26 @@ nl_parse_route(struct krt_proto *p, struct nlmsghdr *h, int scan)
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DBG("Got %I/%d, type=%d, oif=%d\n", dst, i->rtm_dst_len, i->rtm_type, oif);
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switch (i->rtm_protocol)
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{
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case RTPROT_REDIRECT:
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src = KRT_SRC_REDIRECT;
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break;
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case RTPROT_KERNEL:
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DBG("Route originated in kernel, ignoring\n");
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return;
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case RTPROT_BIRD:
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if (!scan)
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{
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DBG("Echo of our own route, ignoring\n");
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return;
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}
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src = KRT_SRC_BIRD;
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break;
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default:
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src = KRT_SRC_ALIEN;
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}
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net = net_get(&master_table, 0, dst, i->rtm_dst_len);
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ra.proto = &p->p;
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ra.source = RTS_INHERIT;
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@ -633,7 +665,11 @@ nl_parse_route(struct krt_proto *p, struct nlmsghdr *h, int scan)
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}
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e = rte_get_temp(&ra);
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e->net = net;
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krt_got_route(p, e);
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e->u.krt_sync.src = src;
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if (scan)
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krt_got_route(p, e);
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else
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krt_got_route_async(p, e, new);
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}
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void
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@ -654,12 +690,72 @@ krt_scan_fire(struct krt_proto *p)
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*/
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static sock *nl_async_sk; /* BIRD socket for asynchronous notifications */
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static byte *nl_async_rx_buffer; /* Receive buffer */
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static void
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nl_async_msg(struct krt_proto *p, struct nlmsghdr *h)
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{
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switch (h->nlmsg_type)
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{
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case RTM_NEWROUTE:
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case RTM_DELROUTE:
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DBG("KRT: Received async route notification (%d)\n", h->nlmsg_type);
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nl_parse_route(p, h, 0);
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break;
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case RTM_NEWLINK:
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case RTM_DELLINK:
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DBG("KRT: Received async link notification (%d)\n", h->nlmsg_type);
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nl_parse_link(h, 0);
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break;
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case RTM_NEWADDR:
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case RTM_DELADDR:
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DBG("KRT: Received async address notification (%d)\n", h->nlmsg_type);
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nl_parse_addr(h);
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break;
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default:
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DBG("KRT: Received unknown async notification (%d)\n", h->nlmsg_type);
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}
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}
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static int
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nl_async_hook(sock *sk, int size)
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{
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DBG("nl_async_hook\n");
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return 0;
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struct krt_proto *p = sk->data;
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struct iovec iov = { nl_async_rx_buffer, NL_RX_SIZE };
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struct sockaddr_nl sa;
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struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
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struct nlmsghdr *h;
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int x;
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unsigned int len;
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nl_last_hdr = NULL; /* Discard packets accidentally remaining in the rxbuf */
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x = recvmsg(sk->fd, &m, 0);
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if (x < 0)
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{
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if (errno != EWOULDBLOCK)
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log(L_ERR "Netlink recvmsg: %m");
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return 0;
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}
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if (sa.nl_pid) /* It isn't from the kernel */
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{
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DBG("Non-kernel packet\n");
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return 1;
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}
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h = (void *) nl_async_rx_buffer;
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len = x;
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if (m.msg_flags & MSG_TRUNC)
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{
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log(L_WARN "Netlink got truncated asynchronous message");
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return 1;
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}
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while (NLMSG_OK(h, len))
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{
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nl_async_msg(p, h);
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h = NLMSG_NEXT(h, len);
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}
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if (len)
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log(L_WARN "nl_async_hook: Found packet remnant of size %d", len);
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return 1;
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}
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static void
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@ -667,21 +763,36 @@ nl_open_async(struct krt_proto *p)
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{
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sock *sk;
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struct sockaddr_nl sa;
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int fd;
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DBG("KRT: Opening async netlink socket\n");
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sk = nl_async_sk = sk_new(p->p.pool);
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sk->type = SK_MAGIC;
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sk->rx_hook = nl_async_hook;
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sk->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
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if (sk->fd < 0 || sk_open(sk))
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die("Unable to open secondary rtnetlink socket: %m");
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fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
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if (fd < 0)
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{
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log(L_ERR "Unable to open secondary rtnetlink socket: %m");
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return;
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}
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bzero(&sa, sizeof(sa));
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sa.nl_family = AF_NETLINK;
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sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE;
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if (bind(sk->fd, (struct sockaddr *) &sa, sizeof(sa)) < 0)
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die("Unable to bind secondary rtnetlink socket: %m");
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if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0)
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{
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log(L_ERR "Unable to bind secondary rtnetlink socket: %m");
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return;
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}
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sk = nl_async_sk = sk_new(p->p.pool);
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sk->type = SK_MAGIC;
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sk->data = p;
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sk->rx_hook = nl_async_hook;
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sk->fd = fd;
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if (sk_open(sk))
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bug("Netlink: sk_open failed");
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if (!nl_async_rx_buffer)
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nl_async_rx_buffer = xmalloc(NL_RX_SIZE);
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}
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/*
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@ -692,6 +803,7 @@ void
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krt_scan_preconfig(struct krt_config *x)
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{
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x->scan.async = 1;
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/* FIXME: Use larger defaults for scanning times? */
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}
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void
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@ -43,7 +43,7 @@ krt_capable_op(rte *e)
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rta *a = e->attrs;
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#ifdef CONFIG_AUTO_ROUTES
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if (a->dest == RTD_ROUTER && a->source == RTS_DEVICE)
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if (a->source == RTS_DEVICE)
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return 0;
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#endif
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return krt_capable(e);
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@ -115,6 +115,7 @@ krt_add_route(rte *new)
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void
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krt_set_notify(struct proto *x, net *net, rte *new, rte *old)
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{
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/* FIXME: Fold remove/add route here */
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if (old)
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krt_remove_route(old);
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if (new)
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@ -78,6 +78,7 @@ krt_got_route(struct krt_proto *p, rte *e)
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{
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rte *old;
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net *net = e->net;
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int src = e->u.krt_sync.src;
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int verdict;
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if (net->n.flags)
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@ -97,7 +98,7 @@ krt_got_route(struct krt_proto *p, rte *e)
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else
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verdict = KRF_UPDATE;
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}
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else if (KRT_CF->learn && !net->routes)
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else if (KRT_CF->learn && !net->routes && (src == KRT_SRC_ALIEN || src < 0))
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verdict = KRF_LEARN;
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else
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verdict = KRF_DELETE;
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@ -188,6 +189,41 @@ krt_prune(struct krt_proto *p)
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FIB_WALK_END;
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}
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void
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krt_got_route_async(struct krt_proto *p, rte *e, int new)
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{
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net *net = e->net;
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rte *old = net->routes;
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int src = e->u.krt_sync.src;
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switch (src)
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{
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case KRT_SRC_BIRD:
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ASSERT(0);
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case KRT_SRC_REDIRECT:
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DBG("It's a redirect, kill him! Kill! Kill!\n");
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krt_set_notify(&p->p, net, NULL, e);
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break;
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default: /* Alien or unspecified */
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if (KRT_CF->learn && new)
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{
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/*
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* FIXME: This is limited to one inherited route per destination as we
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* use single protocol for all inherited routes. Probably leave it
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* as-is (and document it :)), because the correct solution is to
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* multiple kernel tables anyway.
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*/
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DBG("Learning\n");
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rte_update(net, &p->p, e);
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}
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else
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{
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DBG("Discarding\n");
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rte_update(net, &p->p, NULL);
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}
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}
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}
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/*
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* Periodic scanning
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*/
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@ -52,6 +52,13 @@ extern struct proto_config *cf_krt;
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#define KRT_CF ((struct krt_config *)p->p.cf)
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void krt_got_route(struct krt_proto *p, struct rte *e);
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void krt_got_route_async(struct krt_proto *p, struct rte *e, int new);
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/* Values for rte->u.krt_sync.src */
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#define KRT_SRC_UNKNOWN -1 /* Nobody knows */
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#define KRT_SRC_BIRD 0 /* Our route (not passed in async mode) */
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#define KRT_SRC_REDIRECT 1 /* Redirect route, delete it */
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#define KRT_SRC_ALIEN 2 /* Route installed by someone else */
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/* krt-scan.c */
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