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-rw-r--r--sysdep/linux/netlink/krt.c249
1 files changed, 247 insertions, 2 deletions
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 = {
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 14:35:43 +0100