add -B BIND_ADDR option

This option enables using multiple NICs to transfer files.

doc/mscp.1.in

@@ -41,6 +41,9 @@ mscp \- copy files over multiple SSH connections
 .BI \-L \ LIMIT_BITRATE\c
 ]
 [\c
+.BI \-B \ BIND_ADDR\c
+]
+[\c
 .BI \-l \ LOGIN_NAME\c
 ]
 [\c
@@ -220,6 +223,13 @@ delivered over SSH. Changing this value is not recommended at present.
 Limits the bitrate, specified with k (K), m (M), and g (G), e.g., 100m
 indicates 100 Mbps.
 
+.TP
+.B \-B \fIBIND_ADDR\fR
+Specifies a local IP address to bind. When multiple -B options are
+specified, SSH connections will be bound to the addresses in a round
+robin manner. This feature enables using multiple NICs having differnt
+IP addresses.
+
 .TP
 .B \-4
 Uses IPv4 addresses only.

doc/mscp.rst

@@ -2,7 +2,7 @@
 MSCP
 ====
 
-:Date: v0.2.4
+:Date: v0.2.4-2-g7b5a970
 
 NAME
 ====
@@ -16,10 +16,11 @@ SYNOPSIS
 *COREMASK* ] [ **-u** *MAX_STARTUPS* ] [ **-I** *INTERVAL* ] [ **-W**
 *CHECKPOINT* ] [ **-R** *CHECKPOINT* ] [ **-s** *MIN_CHUNK_SIZE* ] [
 **-S** *MAX_CHUNK_SIZE* ] [ **-a** *NR_AHEAD* ] [ **-b** *BUF_SIZE* ] [
-**-L** *LIMIT_BITRATE* ] [ **-l** *LOGIN_NAME* ] [ **-P** *PORT* ] [
+**-L** *LIMIT_BITRATE* ] [ **-B** *BIND_ADDR* ] [ **-l** *LOGIN_NAME* ]
-**-F** *SSH_CONFIG* ] [ **-o** *SSH_OPTION* ] [ **-i** *IDENTITY* ] [
+[ **-P** *PORT* ] [ **-F** *SSH_CONFIG* ] [ **-o** *SSH_OPTION* ] [
-**-J** *DESTINATION* ] [ **-c** *CIPHER* ] [ **-M** *HMAC* ] [ **-C**
+**-i** *IDENTITY* ] [ **-J** *DESTINATION* ] [ **-c** *CIPHER* ] [
-*COMPRESS* ] [ **-g** *CONGESTION* ] *source ... target*
+**-M** *HMAC* ] [ **-C** *COMPRESS* ] [ **-g** *CONGESTION* ] *source
+... target*
 
 DESCRIPTION
 ===========
@@ -120,6 +121,12 @@ OPTIONS
    Limits the bitrate, specified with k (K), m (M), and g (G), e.g.,
    100m indicates 100 Mbps.
 
+**-B BIND_ADDR**
+   Specifies a local IP address to bind. When multiple -B options are
+   specified, SSH connections will be bound to the addresses in a round
+   robin manner. This feature enables using multiple NICs having
+   differnt IP addresses.
+
 **-4**
    Uses IPv4 addresses only.
 

include/mscp.h

@@ -30,6 +30,7 @@
 #include <limits.h>
 #include <stdlib.h>
 
+
 #define MSCP_DIRECTION_L2R	1	/** Indicates local to remote copy */
 #define MSCP_DIRECTION_R2L	2	/** Indicates remote to local copy */
 
@@ -60,6 +61,7 @@ struct mscp_ssh_opts {
 	/* ssh options */
 	char	*login_name;	/** ssh username */
 	char	*port;		/** ssh port */
+	char    **bind_addrs;   /** addresses to bind, terminated by NULL  */
 	int	ai_family;	/** address family */
 	char	*config;	/** path to ssh_config, default ~/.ssh/config*/
 	char	**options;	/** array of ssh_config options, terminated by NULL */

src/main.c

@@ -28,7 +28,7 @@ void usage(bool print_help)
 	       "Usage: mscp [-46vqDpdNh] [-n nr_conns] [-m coremask] [-u max_startups]\n"
 	       "            [-I interval] [-W checkpoint] [-R checkpoint]\n"
 	       "            [-s min_chunk_sz] [-S max_chunk_sz] [-a nr_ahead]\n"
-	       "            [-b buf_sz] [-L limit_bitrate]\n"
+	       "            [-b buf_sz] [-L limit_bitrate] [-B bind_addr]\n"
 	       "            [-l login_name] [-P port] [-F ssh_config] [-o ssh_option]\n"
 	       "            [-i identity_file] [-J destination] [-c cipher_spec] [-M hmac_spec]\n"
 	       "            [-C compress] [-g congestion]\n"
@@ -51,7 +51,8 @@ void usage(bool print_help)
 	       "    -S MAX_CHUNK_SIZE  max chunk size (default: filesize/nr_conn/4)\n"
 	       "    -a NR_AHEAD        number of inflight SFTP commands (default: 32)\n"
 	       "    -b BUF_SZ          buffer size for i/o and transfer\n"
-	       "    -L LIMIT_BITRATE   Limit the bitrate, n[KMG] (default: 0, no limit)\n"
+	       "    -L LIMIT_BITRATE   limit the bitrate, n[KMG] (default: 0, no limit)\n"
+	       "    -B BIND_ADDR       bind address (accept multiple times)\n"
 	       "\n"
 	       "    -4                 use IPv4\n"
 	       "    -6                 use IPv6\n"
@@ -360,13 +361,14 @@ int main(int argc, char **argv)
 	int direction = 0;
 	char *remote = NULL, *checkpoint_save = NULL, *checkpoint_load = NULL;
 	bool quiet = false, dryrun = false, resume = false;
+	int nr_baddrs = 0;
 	int nr_options = 0;
 
 	memset(&s, 0, sizeof(s));
 	memset(&o, 0, sizeof(o));
 	o.severity = MSCP_SEVERITY_WARN;
 
-#define mscpopts "n:m:u:I:W:R:s:S:a:b:L:46vqDrl:P:F:o:i:J:c:M:C:g:pdNh"
+#define mscpopts "n:m:u:I:W:R:s:S:a:b:L:B:46vqDrl:P:F:o:i:J:c:M:C:g:pdNh"
 	while ((ch = getopt(argc, argv, mscpopts)) != -1) {
 		switch (ch) {
 		case 'n':
@@ -407,6 +409,17 @@ int main(int argc, char **argv)
 		case 'L':
 			o.bitrate = atol_with_unit(optarg, false);
 			break;
+		case 'B':
+			nr_baddrs++;
+			s.bind_addrs = realloc(s.bind_addrs,
+					       sizeof(char *) * (nr_baddrs + 1));
+			if (!s.bind_addrs) {
+				pr_err("realloc: %s", strerrno());
+				return 1;
+			}
+			s.bind_addrs[nr_baddrs - 1] = optarg;
+			s.bind_addrs[nr_baddrs] = NULL;
+			break;
 		case '4':
 			s.ai_family = AF_INET;
 			break;

src/ssh.c

@@ -6,6 +6,7 @@
 
 #include <ssh.h>
 #include <mscp.h>
+#include <atomic.h>
 #include <strerrno.h>
 
 #include "libssh/callbacks.h"
@@ -14,6 +15,9 @@
 static int ssh_verify_known_hosts(ssh_session session);
 static int ssh_authenticate_kbdint(ssh_session session);
 
+static lock bind_addr_lock = PTHREAD_MUTEX_INITIALIZER;
+static int bind_addr_idx;
+
 static int ssh_set_opts(ssh_session ssh, struct mscp_ssh_opts *opts)
 {
 	ssh_set_log_level(opts->debug_level);
@@ -29,6 +33,21 @@ static int ssh_set_opts(ssh_session ssh, struct mscp_ssh_opts *opts)
 		return -1;
 	}
 
+	if (opts->bind_addrs) {
+		/* ssh_set_opts can be called from multiple threads,
+		 * thus protect bind_addr_idx with a lock. */
+		char *bind_addr;
+		LOCK_ACQUIRE(&bind_addr_lock);
+		bind_addr = opts->bind_addrs[bind_addr_idx];
+		bind_addr_idx = (opts->bind_addrs[bind_addr_idx + 1] == NULL ?
+				 0 : bind_addr_idx + 1);
+		LOCK_RELEASE();
+		if (ssh_options_set(ssh, SSH_OPTIONS_BINDADDR, bind_addr) < 0) {
+			priv_set_errv("failed to set bind address %s", bind_addr);
+			return -1;
+		}
+	}
+
 	if (opts->ai_family &&
 	    ssh_options_set(ssh, SSH_OPTIONS_AI_FAMILY, &opts->ai_family) < 0) {
 		priv_set_errv("failed to set address family");