The branch stable/14 has been updated by markj:
URL:
https://cgit.FreeBSD.org/src/commit/?id=3ff5faee9e753e70191bb17489600dceaee0424a
commit 3ff5faee9e753e70191bb17489600dceaee0424a
Author: Mark Johnston <ma...@freebsd.org>
AuthorDate: 2025-02-04 16:45:21 +0000
Commit: Mark Johnston <ma...@freebsd.org>
CommitDate: 2025-02-21 01:04:50 +0000
tools: Add a small program to demonstrate FIB handling in bind(2)
MFC after: 2 weeks
Sponsored by: Klara, Inc.
Sponsored by: Stormshield
(cherry picked from commit 3fa552149885766b009d95d20bdf651786fac7b7)
---
tools/tools/fib_multibind/Makefile | 4 +
tools/tools/fib_multibind/sink.c | 237 +++++++++++++++++++++++++++++++++++++
2 files changed, 241 insertions(+)
diff --git a/tools/tools/fib_multibind/Makefile
b/tools/tools/fib_multibind/Makefile
new file mode 100644
index 000000000000..1d447e788a4f
--- /dev/null
+++ b/tools/tools/fib_multibind/Makefile
@@ -0,0 +1,4 @@
+PROG= sink
+MAN=
+
+.include <bsd.prog.mk>
diff --git a/tools/tools/fib_multibind/sink.c b/tools/tools/fib_multibind/sink.c
new file mode 100644
index 000000000000..fe93a66fe266
--- /dev/null
+++ b/tools/tools/fib_multibind/sink.c
@@ -0,0 +1,237 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2025 Klara, Inc.
+ */
+
+/*
+ * A program to demonstrate the effects of the net.inet.tcp.bind_all_fibs and
+ * net.inet.udp.bind_all_fibs sysctls when they are set to 0.
+ *
+ * The program accepts TCP connections (default) or UDP datagrams (-u flag) and
+ * prints the FIB on which they were received, then discards them. If -a is
+ * specific, the program accepts data from all FIBs, otherwise it only accepts
+ * data from the FIB specified by the -f option.
+ */
+
+#include <sys/event.h>
+#include <sys/socket.h>
+#include <sys/sysctl.h>
+
+#include <netinet/in.h>
+
+#include <err.h>
+#include <netdb.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+struct sink_softc {
+ struct sockaddr_storage ss;
+ enum { SINK_TCP, SINK_UDP } type;
+ int nfibs;
+ int kq;
+ int *fds;
+};
+
+static void _Noreturn
+usage(void)
+{
+ fprintf(stderr,
+ "usage: sink [-au] [-f <fib>] [<listen addr>] <listen port>\n");
+ exit(1);
+}
+
+static void
+check_multibind(struct sink_softc *sc)
+{
+ const char *sysctl;
+ size_t len;
+ int error, val;
+
+ sysctl = sc->type == SINK_TCP ? "net.inet.tcp.bind_all_fibs" :
+ "net.inet.udp.bind_all_fibs";
+ len = sizeof(val);
+ error = sysctlbyname(sysctl, &val, &len, NULL, 0);
+ if (error != 0)
+ err(1, "sysctlbyname(%s)", sysctl);
+ if (val != 0)
+ errx(1, "multibind is disabled, set %s=0 to enable", sysctl);
+}
+
+static void
+addrinfo(struct sink_softc *sc, const char *addr, int port)
+{
+ struct addrinfo hints, *res, *res1;
+ char portstr[8];
+ int error;
+
+ memset(&sc->ss, 0, sizeof(sc->ss));
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_socktype = sc->type == SINK_TCP ? SOCK_STREAM : SOCK_DGRAM;
+ snprintf(portstr, sizeof(portstr), "%d", port);
+ error = getaddrinfo(addr, portstr, &hints, &res);
+ if (error != 0)
+ errx(1, "%s", gai_strerror(error));
+ for (res1 = res; res != NULL; res = res->ai_next) {
+ if ((res->ai_protocol == IPPROTO_TCP && sc->type == SINK_TCP) ||
+ (res->ai_protocol == IPPROTO_UDP && sc->type == SINK_UDP)) {
+ memcpy(&sc->ss, res->ai_addr, res->ai_addrlen);
+ break;
+ }
+ }
+ if (res == NULL) {
+ errx(1, "no %s address found for '%s'",
+ sc->type == SINK_TCP ? "TCP" : "UDP", addr);
+ }
+ freeaddrinfo(res1);
+}
+
+int
+main(int argc, char **argv)
+{
+ struct sink_softc sc;
+ const char *laddr;
+ int ch, error, fib, lport;
+ bool all;
+
+ all = false;
+ sc.type = SINK_TCP;
+ fib = -1;
+ while ((ch = getopt(argc, argv, "af:u")) != -1) {
+ switch (ch) {
+ case 'a':
+ all = true;
+ break;
+ case 'f':
+ fib = atoi(optarg);
+ break;
+ case 'u':
+ sc.type = SINK_UDP;
+ break;
+ default:
+ usage();
+ break;
+ }
+ }
+ argc -= optind;
+ argv += optind;
+
+ if (all && fib != -1)
+ errx(1, "-a and -f are mutually exclusive");
+ if (fib == -1) {
+ size_t len;
+
+ error = sysctlbyname("net.my_fibnum", &fib, &len, NULL, 0);
+ if (error != 0)
+ err(1, "sysctlbyname(net.my_fibnum)");
+ }
+
+ if (argc == 2) {
+ laddr = argv[0];
+ lport = atoi(argv[1]);
+ } else if (argc == 1) {
+ laddr = NULL;
+ lport = atoi(argv[0]);
+ } else {
+ usage();
+ }
+ addrinfo(&sc, laddr, lport);
+
+ check_multibind(&sc);
+
+ sc.kq = kqueue();
+ if (sc.kq == -1)
+ err(1, "kqueue");
+
+ if (all) {
+ size_t len;
+
+ len = sizeof(sc.nfibs);
+ error = sysctlbyname("net.fibs", &sc.nfibs, &len, NULL, 0);
+ if (error != 0)
+ err(1, "sysctlbyname(net.fibs)");
+ } else {
+ sc.nfibs = 1;
+ }
+
+ sc.fds = calloc(all ? sc.nfibs : 1, sizeof(int));
+ if (sc.fds == NULL)
+ err(1, "calloc");
+ for (int i = 0; i < sc.nfibs; i++) {
+ struct kevent kev;
+ int s;
+
+ if (sc.type == SINK_TCP)
+ s = socket(sc.ss.ss_family, SOCK_STREAM, 0);
+ else
+ s = socket(sc.ss.ss_family, SOCK_DGRAM, 0);
+ if (s == -1)
+ err(1, "socket");
+ error = setsockopt(s, SOL_SOCKET, SO_SETFIB,
+ all ? &i : &fib, sizeof(int));
+ if (error != 0)
+ err(1, "setsockopt(SO_SETFIB)");
+
+ error = bind(s, (struct sockaddr *)&sc.ss, sc.ss.ss_len);
+ if (error != 0)
+ err(1, "bind");
+
+ if (sc.type == SINK_TCP) {
+ error = listen(s, 5);
+ if (error != 0)
+ err(1, "listen");
+ }
+
+ EV_SET(&kev, s, EVFILT_READ, EV_ADD, 0, 0, NULL);
+ error = kevent(sc.kq, &kev, 1, NULL, 0, NULL);
+ if (error != 0)
+ err(1, "kevent");
+
+ sc.fds[i] = s;
+ }
+
+ for (;;) {
+ struct kevent kev;
+ socklen_t optlen;
+ int n;
+
+ n = kevent(sc.kq, NULL, 0, &kev, 1, NULL);
+ if (n == -1)
+ err(1, "kevent");
+ if (n == 0)
+ continue;
+
+ optlen = sizeof(fib);
+ error = getsockopt((int)kev.ident, SOL_SOCKET, SO_FIB,
+ &fib, &optlen);
+ if (error == -1)
+ err(1, "getsockopt(SO_FIB)");
+
+ if (sc.type == SINK_TCP) {
+ int cs;
+
+ printf("accepting connection from FIB %d\n", fib);
+
+ cs = accept((int)kev.ident, NULL, NULL);
+ if (cs == -1)
+ err(1, "accept");
+ close(cs);
+ } else {
+ char buf[1024];
+ ssize_t nb;
+
+ printf("receiving datagram from FIB %d\n", fib);
+
+ nb = recvfrom((int)kev.ident, buf, sizeof(buf), 0,
+ NULL, NULL);
+ if (nb == -1)
+ err(1, "recvfrom");
+ }
+ }
+
+ return (0);
+}
