enh: Support SO_BINDTODEVICE

This lets iperf work better with multi-homed machines and
VRF.

Towards #1089.

Based on a patch by Ben Greear <greearb@candelatech.com> via PR #817.

src/iperf.h

@@ -40,6 +40,7 @@
 # define _GNU_SOURCE
 #endif
 #include <netinet/tcp.h>
+#include <net/if.h> // for IFNAMSIZ
 
 #if defined(HAVE_CPUSET_SETAFFINITY)
 #include <sys/param.h>
@@ -258,6 +259,7 @@ struct iperf_test
     char     *server_hostname;                  /* -c option */
     char     *tmp_template;
     char     *bind_address;                     /* first -B option */
+    char     *bind_dev;                         /* bind to network device */
     TAILQ_HEAD(xbind_addrhead, xbind_entry) xbind_addrs; /* all -X opts */
     int       bind_port;                        /* --cport option */
     int       server_port;

src/iperf3.1

@@ -139,6 +139,10 @@ CPUs).
 .TP
 .BR -B ", " --bind " \fIhost\fR"
 bind to the specific interface associated with address \fIhost\fR.
+.BR --bind-dev " \fIdev\R"
+bind to the specified network interface.
+This option uses SO_BINDTODEVICE, and may require root permissions.
+(Available on Linux and possibly other systems.)
 .TP
 .BR -V ", " --verbose " "
 give more detailed output 

src/iperf_api.c

@@ -339,6 +339,12 @@ iperf_get_test_bind_address(struct iperf_test *ipt)
     return ipt->bind_address;
 }
 
+char *
+iperf_get_test_bind_dev(struct iperf_test *ipt)
+{
+    return ipt->bind_dev;
+}
+
 int
 iperf_get_test_udp_counters_64bit(struct iperf_test *ipt)
 {
@@ -661,6 +667,12 @@ iperf_set_test_bind_address(struct iperf_test *ipt, const char *bnd_address)
     ipt->bind_address = strdup(bnd_address);
 }
 
+void
+iperf_set_test_bind_dev(struct iperf_test *ipt, char *bnd_dev)
+{
+    ipt->bind_dev = strdup(bnd_dev);
+}
+
 void
 iperf_set_test_udp_counters_64bit(struct iperf_test *ipt, int udp_counters_64bit)
 {
@@ -894,6 +906,7 @@ iperf_parse_arguments(struct iperf_test *test, int argc, char **argv)
         {"bidir", no_argument, NULL, OPT_BIDIRECTIONAL},
         {"window", required_argument, NULL, 'w'},
         {"bind", required_argument, NULL, 'B'},
+        {"bind-dev", required_argument, NULL, OPT_BIND_DEV},
         {"cport", required_argument, NULL, OPT_CLIENT_PORT},
         {"set-mss", required_argument, NULL, 'M'},
         {"no-delay", no_argument, NULL, 'N'},
@@ -1147,6 +1160,9 @@ iperf_parse_arguments(struct iperf_test *test, int argc, char **argv)
             case 'B':
                 test->bind_address = strdup(optarg);
                 break;
+            case OPT_BIND_DEV:
+                test->bind_dev = strdup(optarg);
+                break;
             case OPT_CLIENT_PORT:
 		portno = atoi(optarg);
 		if (portno < 1 || portno > 65535) {
@@ -2635,6 +2651,8 @@ iperf_free_test(struct iperf_test *test)
 	free(test->tmp_template);
     if (test->bind_address)
 	free(test->bind_address);
+    if (test->bind_dev)
+	free(test->bind_dev);
     if (!TAILQ_EMPTY(&test->xbind_addrs)) {
         struct xbind_entry *xbe;
 

src/iperf_api.h

@@ -80,6 +80,7 @@ typedef uint64_t iperf_size_t;
 #define OPT_SERVER_BITRATE_LIMIT 21
 #define OPT_TIMESTAMPS 22
 #define OPT_SERVER_SKEW_THRESHOLD 23
+#define OPT_BIND_DEV 24
 
 /* states */
 #define TEST_START 1
@@ -408,6 +409,7 @@ enum {
     IESETPACING= 140,       // Unable to set socket pacing rate
     IESETBUF2= 141,	    // Socket buffer size incorrect (written value != read value)
     IEAUTHTEST = 142,       // Test authorization failed
+    IEBINDDEV = 143,        // Unable to bind-to-device (check perror, maybe permissions?)
     /* Stream errors */
     IECREATESTREAM = 200,   // Unable to create a new stream (check herror/perror)
     IEINITSTREAM = 201,     // Unable to initialize stream (check herror/perror)

src/iperf_client_api.c

@@ -336,7 +336,7 @@ iperf_connect(struct iperf_test *test)
     /* Create and connect the control channel */
     if (test->ctrl_sck < 0)
 	// Create the control channel using an ephemeral port
-	test->ctrl_sck = netdial(test->settings->domain, Ptcp, test->bind_address, 0, test->server_hostname, test->server_port, test->settings->connect_timeout);
+	test->ctrl_sck = netdial(test->settings->domain, Ptcp, test->bind_address, test->bind_dev, 0, test->server_hostname, test->server_port, test->settings->connect_timeout);
     if (test->ctrl_sck < 0) {
         i_errno = IECONNECT;
         return -1;

src/iperf_locale.c

@@ -105,6 +105,7 @@ const char usage_longstr[] = "Usage: iperf3 [-s|-c host] [options]\n"
                            "  -A, --affinity n/n,m      set CPU affinity\n"
 #endif /* HAVE_CPU_AFFINITY */
                            "  -B, --bind      <host>    bind to the interface associated with the address <host>\n"
+                           "  --bind-dev      <dev>     bind to the network interface with SO_BINDTODEVICE\n"
                            "  -V, --verbose             more detailed output\n"
                            "  -J, --json                output in JSON format\n"
                            "  --logfile f               send output to a log file\n"
@@ -233,6 +234,9 @@ const char client_port[] =
 const char bind_address[] =
 "Binding to local address %s\n";
 
+const char bind_dev[] =
+"Binding to local network device %s\n";
+
 const char bind_port[] =
 "Binding to local port %s\n";
 

src/iperf_locale.h

@@ -36,6 +36,7 @@ extern const char seperator_line[];
 extern const char server_port[] ;
 extern const char client_port[] ;
 extern const char bind_address[] ;
+extern const char bind_dev[] ;
 extern const char multicast_ttl[] ;
 extern const char join_multicast[] ;
 extern const char client_datagram_size[] ;

src/iperf_sctp.c

@@ -211,6 +211,21 @@ iperf_sctp_listen(struct iperf_test *test)
         }
     }
 
+    if (test->bind_dev) {
+#ifdef SO_BINDTODEVICE
+        if (setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE,
+                       test->bind_dev, IFNAMSIZ) < 0)
+#endif
+        {
+            saved_errno = errno;
+            close(s);
+            freeaddrinfo(res);
+            i_errno = IEBINDDEV;
+            errno = saved_errno;
+            return -1;
+        }
+    }
+
 #if defined(IPV6_V6ONLY) && !defined(__OpenBSD__)
     if (res->ai_family == AF_INET6 && (test->settings->domain == AF_UNSPEC || 
         test->settings->domain == AF_INET6)) {
@@ -284,7 +299,7 @@ iperf_sctp_connect(struct iperf_test *test)
 #if defined(HAVE_SCTP_H)
     int s, opt, saved_errno;
     char portstr[6];
-    struct addrinfo hints, *local_res, *server_res;
+    struct addrinfo hints, *local_res = NULL, *server_res = NULL;
 
     if (test->bind_address) {
         memset(&hints, 0, sizeof(hints));
@@ -309,8 +324,7 @@ iperf_sctp_connect(struct iperf_test *test)
 
     s = socket(server_res->ai_family, SOCK_STREAM, IPPROTO_SCTP);
     if (s < 0) {
-	if (test->bind_address)
-	    freeaddrinfo(local_res);
+	freeaddrinfo(local_res);
 	freeaddrinfo(server_res);
         i_errno = IESTREAMCONNECT;
         return -1;
@@ -336,6 +350,22 @@ iperf_sctp_connect(struct iperf_test *test)
         }
     }
 
+    if (test->bind_dev) {
+#ifdef SO_BINDTODEVICE
+        if (setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE,
+                       test->bind_dev, IFNAMSIZ) < 0)
+#endif
+        {
+            saved_errno = errno;
+            close(s);
+            freeaddrinfo(local_res);
+            freeaddrinfo(server_res);
+            i_errno = IEBINDDEV;
+            errno = saved_errno;
+            return -1;
+        }
+    }
+
     /*
      * Various ways to bind the local end of the connection.
      * 1.  --bind (with or without --cport).

src/iperf_server_api.c

@@ -70,7 +70,7 @@ int
 iperf_server_listen(struct iperf_test *test)
 {
     retry:
-    if((test->listener = netannounce(test->settings->domain, Ptcp, test->bind_address, test->server_port)) < 0) {
+    if((test->listener = netannounce(test->settings->domain, Ptcp, test->bind_address, test->bind_dev, test->server_port)) < 0) {
 	if (errno == EAFNOSUPPORT && (test->settings->domain == AF_INET6 || test->settings->domain == AF_UNSPEC)) {
 	    /* If we get "Address family not supported by protocol", that
 	    ** probably means we were compiled with IPv6 but the running
@@ -609,7 +609,7 @@ iperf_run_server(struct iperf_test *test)
                             FD_CLR(test->listener, &test->read_set);
                             close(test->listener);
 			    test->listener = 0;
-                            if ((s = netannounce(test->settings->domain, Ptcp, test->bind_address, test->server_port)) < 0) {
+                            if ((s = netannounce(test->settings->domain, Ptcp, test->bind_address, test->bind_dev, test->server_port)) < 0) {
 				cleanup_server(test);
                                 i_errno = IELISTEN;
                                 return -1;

src/iperf_udp.c

@@ -440,7 +440,7 @@ iperf_udp_accept(struct iperf_test *test)
     /*
      * Create a new "listening" socket to replace the one we were using before.
      */
-    test->prot_listener = netannounce(test->settings->domain, Pudp, test->bind_address, test->server_port);
+    test->prot_listener = netannounce(test->settings->domain, Pudp, test->bind_address, test->bind_dev, test->server_port);
     if (test->prot_listener < 0) {
         i_errno = IESTREAMLISTEN;
         return -1;
@@ -472,7 +472,7 @@ iperf_udp_listen(struct iperf_test *test)
 {
     int s;
 
-    if ((s = netannounce(test->settings->domain, Pudp, test->bind_address, test->server_port)) < 0) {
+    if ((s = netannounce(test->settings->domain, Pudp, test->bind_address, test->bind_dev, test->server_port)) < 0) {
         i_errno = IESTREAMLISTEN;
         return -1;
     }
@@ -499,7 +499,7 @@ iperf_udp_connect(struct iperf_test *test)
     int rc;
 
     /* Create and bind our local socket. */
-    if ((s = netdial(test->settings->domain, Pudp, test->bind_address, test->bind_port, test->server_hostname, test->server_port, -1)) < 0) {
+    if ((s = netdial(test->settings->domain, Pudp, test->bind_address, test->bind_dev, test->bind_port, test->server_hostname, test->server_port, -1)) < 0) {
         i_errno = IESTREAMCONNECT;
         return -1;
     }

src/libiperf.3

@@ -25,6 +25,7 @@ Setting test parameters:
 .nf
     void iperf_set_test_role( struct iperf_test *pt, char role );
     void iperf_set_test_bind_address( struct iperf_test *t, char *bind_address );
+    void iperf_set_test_bind_dev( struct iperf_test *t, char *bind_dev );
     void iperf_set_test_server_hostname( struct iperf_test *t, char *server_host );
     void iperf_set_test_server_port( struct iperf_test *t, int server_port );
     void iperf_set_test_duration( struct iperf_test *t, int duration );

src/net.c

@@ -61,6 +61,7 @@
 #include <poll.h>
 #endif /* HAVE_POLL_H */
 
+#include "iperf.h"
 #include "iperf_util.h"
 #include "net.h"
 #include "timer.h"
@@ -121,9 +122,9 @@ timeout_connect(int s, const struct sockaddr *name, socklen_t namelen,
 
 /* make connection to server */
 int
-netdial(int domain, int proto, const char *local, int local_port, const char *server, int port, int timeout)
+netdial(int domain, int proto, const char *local, const char *bind_dev, int local_port, const char *server, int port, int timeout)
 {
-    struct addrinfo hints, *local_res, *server_res;
+    struct addrinfo hints, *local_res = NULL, *server_res = NULL;
     int s, saved_errno;
 
     if (local) {
@@ -148,6 +149,21 @@ netdial(int domain, int proto, const char *local, int local_port, const char *se
         return -1;
     }
 
+    if (bind_dev) {
+#ifdef SO_BINDTODEVICE
+        if (setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE,
+                       bind_dev, IFNAMSIZ) < 0)
+#endif
+        {
+            saved_errno = errno;
+            close(s);
+            freeaddrinfo(local_res);
+            freeaddrinfo(server_res);
+            errno = saved_errno;
+            return -1;
+        }
+    }
+
     /* Bind the local address if given a name (with or without --cport) */
     if (local) {
         if (local_port) {
@@ -218,7 +234,7 @@ netdial(int domain, int proto, const char *local, int local_port, const char *se
 /***************************************************************/
 
 int
-netannounce(int domain, int proto, const char *local, int port)
+netannounce(int domain, int proto, const char *local, const char *bind_dev, int port)
 {
     struct addrinfo hints, *res;
     char portstr[6];
@@ -255,6 +271,20 @@ netannounce(int domain, int proto, const char *local, int port)
         return -1;
     }
 
+    if (bind_dev) {
+#ifdef SO_BINDTODEVICE
+        if (setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE,
+                       bind_dev, IFNAMSIZ) < 0)
+#endif
+        {
+            saved_errno = errno;
+            close(s);
+            freeaddrinfo(res);
+            errno = saved_errno;
+            return -1;
+        }
+    }
+
     opt = 1;
     if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, 
 		   (char *) &opt, sizeof(opt)) < 0) {

src/net.h

@@ -28,8 +28,8 @@
 #define __NET_H
 
 int timeout_connect(int s, const struct sockaddr *name, socklen_t namelen, int timeout);
-int netdial(int domain, int proto, const char *local, int local_port, const char *server, int port, int timeout);
-int netannounce(int domain, int proto, const char *local, int port);
+int netdial(int domain, int proto, const char *local, const char *bind_dev, int local_port, const char *server, int port, int timeout);
+int netannounce(int domain, int proto, const char *local, const char *bind_dev, int port);
 int Nread(int fd, char *buf, size_t count, int prot);
 int Nwrite(int fd, const char *buf, size_t count, int prot) /* __attribute__((hot)) */;
 int has_sendfile(void);