diff options
Diffstat (limited to '')
| -rw-r--r-- | capture/iface_monitor.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/capture/iface_monitor.c b/capture/iface_monitor.c index f742a664..870761ca 100644 --- a/capture/iface_monitor.c +++ b/capture/iface_monitor.c @@ -17,6 +17,8 @@ /* * Linux with libnl. + * + * Use Netlink to get indications of new/removed intrfaces. */ #include <stdio.h> @@ -181,6 +183,8 @@ iface_mon_stop(void) /* * macOS. + * + * Use a PF_SYSTEM socket to get indications of new/removed intrfaces. */ #include <stddef.h> @@ -354,6 +358,176 @@ iface_mon_event(void) } } +#elif defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) + +/* + * FreeBSD, NetBSD, OpenBSD, DragonFly BSD. + * + * Use a PF_ROUTE socket to get indications of new/removed intrfaces. + */ +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <unistd.h> + +#include <sys/types.h> +#include <sys/socket.h> +#include <net/if.h> +#include <net/route.h> +#include <net/if_dl.h> + +#include <netinet/in.h> +#include <netinet/in_var.h> + +static int s; +static iface_mon_cb callback; + +int +iface_mon_start(iface_mon_cb cb) +{ +#ifdef RO_MSGFILTER + unsigned char msgfilter[] = { + RTM_IFANNOUNCE, + }; +#endif + + /* Create a socket of type PF_ROUTE to listen for events. */ + s = socket(PF_ROUTE, SOCK_RAW, 0); + if (s == -1) + return -errno; + +#ifdef RO_MSGFILTER + /* + * This OS supports filtering PF_ROUTE sockets for specific + * events; we only want interface announcement events. + * + * If this fails, we just live with extra events that we ignore, + * which we also do on platforms that don't support filtering. + */ + (void) setsockopt(s, PF_ROUTE, RO_MSGFILTER, &msgfilter, sizeof msgfilter); +#endif +#ifdef SO_RERROR + /* + * This OS supports getting error reports from recvmsg() if a + * receive buffer overflow occurs. If that happens, it means + * that we may have lost interface reports, so we should + * probably just refetch all interface data. + * + * If we can't get those error reports, we're out of luck. + */ + int n = 1; + (void) setsockopt(s, SOL_SOCKET, SO_RERROR, &n, sizeof(n)); +#endif + + callback = cb; + return 0; +} + +void +iface_mon_stop(void) +{ + close(s); +} + +int +iface_mon_get_sock(void) +{ + return s; +} + +void +iface_mon_event(void) +{ + union msgbuf { + char buf[2048]; + struct rt_msghdr hd; + struct if_announcemsghdr ifan; + } msgbuf; + struct iovec iov[1]; + struct msghdr msg; + bool message_seen = false; + ssize_t received; + + iov[0].iov_base = &msgbuf; + iov[0].iov_len = sizeof msgbuf; + memset(&msg, 0, sizeof msg); + msg.msg_iov = iov; + msg.msg_iovlen = 1; + + while (!message_seen) { + received = recvmsg(s, &msg, 0); + if (received == -1) { + if (errno == ENOBUFS) { + /* + * Receive buffer overflow. Keep reading, + * to get any messages in the socket buffer. + * + * XXX - that means we may have lost indications; + * should there be a callback that indicates that + * all interface data should be refreshed? + */ + continue; + } else { + /* + * Other error - just ignore. + */ + return; + } + } + + /* + * We've seen a message. + */ + message_seen = true; + } + if (received != 0) { + /* + * XXX - should we check received, to make sure it's large + * enough? + */ + if (msgbuf.hd.rtm_version != RTM_VERSION) + return; + + switch (msgbuf.hd.rtm_type) { + + case RTM_IFANNOUNCE: + switch (msgbuf.ifan.ifan_what) { + + case IFAN_ARRIVAL: + /* + * A new interface has arrived. + * + * XXX - see comment about interface arrivals in the + * macOS section; it applies here as well. + */ + callback(msgbuf.ifan.ifan_name, 1, 1); + break; + + case IFAN_DEPARTURE: + /* + * An existing interface has been removed. + */ + callback(msgbuf.ifan.ifan_name, 0, 0); + break; + + default: + /* + * Ignore other notifications. + */ + break; + } + break; + + default: + /* + * Ignore other messages. + */ + break; + } + } +} + #else /* don't have something we support */ int |