sockopts: support many more socket options, including strings

Add support for many more socket options, including those that take
string inputs, such as `TCP_CONGESTION=bbr`.

Options known to the code, but not present at build time will now emit
an error that is distict from options unknown to the code (unknown vs
not-available).

This patch greatly eases running specific rsync configurations, without
relying on LD_PRELOAD to modify socket behaviors.

Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>

Author: robbat2

.gitignore

@@ -58,3 +58,4 @@ aclocal.m4
 /auto-build-save
 .deps
 /*.exe
+/sockopts.c

Makefile.in

@@ -47,7 +47,7 @@ OBJS1=flist.o rsync.o generator.o receiver.o cleanup.o sender.o exclude.o \
 	util1.o util2.o main.o checksum.o match.o syscall.o log.o backup.o delete.o
 OBJS2=options.o io.o compat.o hlink.o token.o uidlist.o socket.o hashtable.o \
 	usage.o fileio.o batch.o clientname.o chmod.o acls.o xattrs.o
-OBJS3=progress.o pipe.o @MD5_ASM@ @ROLL_SIMD@ @ROLL_ASM@
+OBJS3=progress.o pipe.o sockopts.o @MD5_ASM@ @ROLL_SIMD@ @ROLL_ASM@
 DAEMON_OBJ = params.o loadparm.o clientserver.o access.o connection.o authenticate.o
 popt_OBJS=popt/findme.o  popt/popt.o  popt/poptconfig.o \
 	popt/popthelp.o popt/poptparse.o
@@ -367,3 +367,7 @@ doxygen:
 doxygen-upload:
 	rsync -avzv $(srcdir)/dox/html/ --delete \
 	$${SAMBA_HOST-samba.org}:/home/httpd/html/rsync/doxygen/head/
+
+# FreeBSD make does not support $<
+sockopts.c: sockopts.c.sh
+	sh $* >$@.tmp && mv $@.tmp $@

NEWS.md

@@ -49,6 +49,10 @@
 - Changed the mapfrom & mapto perl scripts (in the support dir) into a single
   python script named idmap.  Converted a couple more perl scripts into python.
 
+- Recognize many more sockopt inputs, including string inputs.
+  e.g. TCP_CONGESTION=bbr, TCP_FASTOPEN, TCP_FASTOPEN_CONNECT, IP_FREEBIND,
+  SO_INCOMING_CPU, TCP_QUICKACK
+
 ### DEVELOPER RELATED:
 
  - Updated config.guess (timestamp 2023-01-01) and config.sub (timestamp

configure.ac

@@ -13,7 +13,7 @@ AC_CHECK_HEADERS(sys/fcntl.h sys/select.h fcntl.h sys/time.h sys/unistd.h \
     sys/acl.h acl/libacl.h attr/xattr.h sys/xattr.h sys/extattr.h dl.h \
     popt.h popt/popt.h linux/falloc.h netinet/in_systm.h netgroup.h \
     zlib.h xxhash.h openssl/md4.h openssl/md5.h zstd.h lz4.h sys/file.h \
-    bsd/string.h)
+    bsd/string.h netinet/ip6.h)
 AC_CHECK_HEADERS([netinet/ip.h], [], [], [[#include <netinet/in.h>]])
 AC_HEADER_MAJOR_FIXED
 

rsync.1.md

@@ -3071,6 +3071,18 @@ expand it.
     able to set.  By default no special socket options are set.  This only
     affects direct socket connections to a remote rsync daemon.
 
+    `OPTIONS` a space or comma seperated list of one or more `optname` strings
+    (e.g. `SO_KEEPALIVE`, `SO_SNDBUF=1234`, `SO_BINDTODEVICE=lo`, `IP_FREEBIND`,
+    `TCP_CONGESTION=reno`, `TCP_FASTOPEN`, `TCP_FASTOPEN_CONNECT`), or `optval`
+    strings (e.g. `IP_PMTUDISC_DO`, `IPTOS_THROUGHPUT`).
+
+    Unknown options are those not know to the source at build time.
+    Unsupported options are those known source code, but not present in the
+    build environment.
+
+    All errors are non-fatal, including unknown options, unsupported options,
+    missing required arguments or superflous arguments.
+
     See also [the daemon version of the `--sockopts` option](#dopt--sockopts).
 
 0.  `--blocking-io`

rsync.h

@@ -1171,6 +1171,24 @@ struct name_num_obj {
 	struct name_num_item *list;
 };
 
+enum SOCK_OPT_TYPES {
+    SOCK_OPT_BOOL,
+    SOCK_OPT_INT,
+    SOCK_OPT_ON,
+    SOCK_OPT_STR,
+    // error sentinal, hopefully never a valid setsockopt level
+    SOCK_OPT_ERR = 0xDEADCAFE
+};
+
+struct socket_option
+{
+	char *name;
+	int level;
+	int option;
+	int value;
+	int opttype;
+};
+
 #ifdef EXTERNAL_ZLIB
 #define read_buf read_buf_
 #endif

socket.c

@@ -40,6 +40,7 @@ extern char *sockopts;
 extern int default_af_hint;
 extern int connect_timeout;
 extern int pid_file_fd;
+extern struct socket_option socket_options[];
 
 #ifdef HAVE_SIGACTION
 static struct sigaction sigact;
@@ -623,53 +624,6 @@ void start_accept_loop(int port, int (*fn)(int, int))
 	}
 }
 
-
-enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
-
-struct
-{
-  char *name;
-  int level;
-  int option;
-  int value;
-  int opttype;
-} socket_options[] = {
-  {"SO_KEEPALIVE",      SOL_SOCKET,    SO_KEEPALIVE,    0,                 OPT_BOOL},
-  {"SO_REUSEADDR",      SOL_SOCKET,    SO_REUSEADDR,    0,                 OPT_BOOL},
-#ifdef SO_BROADCAST
-  {"SO_BROADCAST",      SOL_SOCKET,    SO_BROADCAST,    0,                 OPT_BOOL},
-#endif
-#ifdef TCP_NODELAY
-  {"TCP_NODELAY",       IPPROTO_TCP,   TCP_NODELAY,     0,                 OPT_BOOL},
-#endif
-#ifdef IPTOS_LOWDELAY
-  {"IPTOS_LOWDELAY",    IPPROTO_IP,    IP_TOS,          IPTOS_LOWDELAY,    OPT_ON},
-#endif
-#ifdef IPTOS_THROUGHPUT
-  {"IPTOS_THROUGHPUT",  IPPROTO_IP,    IP_TOS,          IPTOS_THROUGHPUT,  OPT_ON},
-#endif
-#ifdef SO_SNDBUF
-  {"SO_SNDBUF",         SOL_SOCKET,    SO_SNDBUF,       0,                 OPT_INT},
-#endif
-#ifdef SO_RCVBUF
-  {"SO_RCVBUF",         SOL_SOCKET,    SO_RCVBUF,       0,                 OPT_INT},
-#endif
-#ifdef SO_SNDLOWAT
-  {"SO_SNDLOWAT",       SOL_SOCKET,    SO_SNDLOWAT,     0,                 OPT_INT},
-#endif
-#ifdef SO_RCVLOWAT
-  {"SO_RCVLOWAT",       SOL_SOCKET,    SO_RCVLOWAT,     0,                 OPT_INT},
-#endif
-#ifdef SO_SNDTIMEO
-  {"SO_SNDTIMEO",       SOL_SOCKET,    SO_SNDTIMEO,     0,                 OPT_INT},
-#endif
-#ifdef SO_RCVTIMEO
-  {"SO_RCVTIMEO",       SOL_SOCKET,    SO_RCVTIMEO,     0,                 OPT_INT},
-#endif
-  {NULL,0,0,0,0}
-};
-
-
 /* Set user socket options. */
 void set_socket_options(int fd, char *options)
 {
@@ -682,13 +636,14 @@ void set_socket_options(int fd, char *options)
 
 	for (tok = strtok(options, " \t,"); tok; tok = strtok(NULL," \t,")) {
 		int ret=0,i;
-		int value = 1;
 		char *p;
+		char *value;
+		int intvalue = 1;
 		int got_value = 0;
 
 		if ((p = strchr(tok,'='))) {
 			*p = 0;
-			value = atoi(p+1);
+			value = p+1;
 			got_value = 1;
 		}
 
@@ -701,16 +656,52 @@ void set_socket_options(int fd, char *options)
 			rprintf(FERROR,"Unknown socket option %s\n",tok);
 			continue;
 		}
+		if(socket_options[i].level == (int)(SOCK_OPT_ERR)) {
+			// At compile-time, a potential socket option was NOT present on
+			// the build system.
+			rprintf(FERROR,"Unsupported socket option %s\n",tok);
+			continue;
+		}
 
 		switch (socket_options[i].opttype) {
-		case OPT_BOOL:
-		case OPT_INT:
-			ret = setsockopt(fd,socket_options[i].level,
-					 socket_options[i].option,
-					 (char *)&value, sizeof (int));
+		case SOCK_OPT_BOOL:
+			if(got_value)
+				intvalue = atoi(value);
+			ret = setsockopt(fd,
+					socket_options[i].level,
+					socket_options[i].option,
+					(char *)&intvalue,
+					sizeof (int)
+					);
+			break;
+
+		case SOCK_OPT_INT:
+			if(got_value) {
+				intvalue = atoi(value);
+				ret = setsockopt(fd,
+						socket_options[i].level,
+						socket_options[i].option,
+						(char *)&intvalue,
+						sizeof (int)
+						);
+			} else {
+				rprintf(FERROR,"syntax error -- %s requires an integer value\n",tok);
+			}
+			break;
+
+		case SOCK_OPT_STR:
+			if (got_value) {
+				ret = setsockopt(fd,
+						socket_options[i].level,
+						socket_options[i].option,
+						value,
+						strlen(value));
+			} else {
+				rprintf(FERROR,"syntax error -- %s requires a string value\n",tok);
+			}
 			break;
 
-		case OPT_ON:
+		case SOCK_OPT_ON:
 			if (got_value)
 				rprintf(FERROR,"syntax error -- %s does not take a value\n",tok);
 

sockopts.c.sh

@@ -0,0 +1,131 @@
+#!/bin/sh
+# vim: noet
+# The "noet" is important because of the -EOF behavior.
+opt() {
+	name=$1
+	level=$2
+	optname=$3
+	optval=$4
+	opttype=$5
+
+	check_optval=1
+	case ${optval} in
+		[A-Z_]*) ;;
+		*) check_optval='' ;;
+	esac
+	# If we have configure --disable-ipv6, the options might be available in
+	# the system headers, but the builder wants to NOT support them.
+	optdef_extra=''
+	case $name in
+		IPV6*) optdef_extra=' && defined(INET6)' ;;
+	esac
+
+	# If the values are NOT available at compile-time, we should recognize the
+	# input and emit an error.
+	cat <<-EOF
+	#if defined(${level}) && defined(${optname}) ${check_optval:+&& defined(${optval})}${optdef_extra}
+	  {"${name}", ${level}, ${optname}, ${optval}, ${opttype}},
+	#else
+	  {"${name}", SOCK_OPT_ERR, SOCK_OPT_ERR, SOCK_OPT_ERR, ${opttype}},
+	#endif
+	EOF
+}
+
+opt_bool() {
+	opt "$1" "$2" "${3:-$1}" 0 SOCK_OPT_BOOL
+}
+opt_int() {
+	opt "$1" "$2" "${3:-$1}" 0 SOCK_OPT_INT
+}
+opt_val() {
+	opt "$1" "$2" "$3" "$4" SOCK_OPT_ON
+}
+opt_str() {
+	opt "$1" "$2" "${3:-$1}" 0 SOCK_OPT_STR
+}
+
+cat <<-EOF
+#include "rsync.h"
+#ifdef HAVE_NETINET_IN_SYSTM_H
+#include <netinet/in_systm.h>
+#endif
+#ifdef HAVE_NETINET_IP_H
+#include <netinet/ip.h>
+#endif
+#ifdef HAVE_NETINET_IP6_H
+#include <netinet/ip6.h>
+#endif
+#include <netinet/tcp.h>
+struct socket_option socket_options[] = {
+EOF
+
+# grouped by level, sorted by name.
+opt_str		SO_BINDTODEVICE			SOL_SOCKET
+opt_bool	SO_BROADCAST			SOL_SOCKET
+opt_int		SO_BUSY_POLL			SOL_SOCKET
+opt_bool	SO_DEBUG				SOL_SOCKET
+opt_bool	SO_DONTROUTE			SOL_SOCKET
+opt_int		SO_INCOMING_CPU			SOL_SOCKET
+opt_bool	SO_KEEPALIVE			SOL_SOCKET
+opt_int		SO_MARK					SOL_SOCKET
+opt_int		SO_PRIORITY				SOL_SOCKET
+opt_int		SO_RCVBUF				SOL_SOCKET
+opt_int		SO_RCVLOWAT				SOL_SOCKET
+opt_int		SO_RCVTIMEO				SOL_SOCKET
+opt_bool	SO_REUSEADDR			SOL_SOCKET
+opt_bool	SO_REUSEPORT			SOL_SOCKET
+opt_int		SO_SNDBUF				SOL_SOCKET
+opt_int		SO_SNDLOWAT				SOL_SOCKET
+opt_int		SO_SNDTIMEO				SOL_SOCKET
+
+opt_bool	IP_BIND_ADDRESS_NO_PORT IPPROTO_IP
+opt_int		IP_CHECKSUM				IPPROTO_IP
+opt_bool	IP_FREEBIND				IPPROTO_IP
+opt_int		IP_LOCAL_PORT_RANGE		IPPROTO_IP
+opt_int		IP_MINTTL				IPPROTO_IP
+opt_int		IP_MTU					IPPROTO_IP
+opt_val		IP_PMTUDISC_DO			IPPROTO_IP	IP_MTU_DISCOVER	IP_PMTUDISC_DO
+opt_val		IP_PMTUDISC_DONT		IPPROTO_IP	IP_MTU_DISCOVER	IP_PMTUDISC_DONT
+opt_val		IP_PMTUDISC_INTERFACE	IPPROTO_IP	IP_MTU_DISCOVER	IP_PMTUDISC_INTERFACE
+opt_val		IP_PMTUDISC_OMIT		IPPROTO_IP	IP_MTU_DISCOVER	IP_PMTUDISC_OMIT
+opt_val		IP_PMTUDISC_PROBE		IPPROTO_IP	IP_MTU_DISCOVER	IP_PMTUDISC_PROBE
+opt_val		IP_PMTUDISC_WANT		IPPROTO_IP	IP_MTU_DISCOVER	IP_PMTUDISC_WANT
+opt_bool	IP_TRANSPARENT			IPPROTO_IP
+
+# sorting exception, to group the IPTOS together.
+opt_val		IPTOS_LOWDELAY			IPPROTO_IP	IP_TOS	IPTOS_LOWDELAY
+opt_val		IPTOS_MINCOST			IPPROTO_IP	IP_TOS	IPTOS_MINCOST
+opt_val		IPTOS_RELIABILITY		IPPROTO_IP	IP_TOS	IPTOS_RELIABILITY
+opt_val		IPTOS_THROUGHPUT		IPPROTO_IP	IP_TOS	IPTOS_THROUGHPUT
+
+opt_bool	IPV6_FREEBIND			IPPROTO_IPV6
+opt_int		IPV6_MTU				IPPROTO_IPV6
+opt_val		IPV6_PMTUDISC_DO		IPPROTO_IPV6	IPV6_MTU_DISCOVER	IPV6_PMTUDISC_DO
+opt_val		IPV6_PMTUDISC_DONT		IPPROTO_IPV6	IPV6_MTU_DISCOVER	IPV6_PMTUDISC_DONT
+opt_val		IPV6_PMTUDISC_INTERFACE	IPPROTO_IPV6	IPV6_MTU_DISCOVER	IPV6_PMTUDISC_INTERFACE
+opt_val		IPV6_PMTUDISC_OMIT		IPPROTO_IPV6	IPV6_MTU_DISCOVER	IPV6_PMTUDISC_OMIT
+opt_val		IPV6_PMTUDISC_PROBE		IPPROTO_IPV6	IPV6_MTU_DISCOVER	IPV6_PMTUDISC_PROBE
+opt_val		IPV6_PMTUDISC_WANT		IPPROTO_IPV6	IPV6_MTU_DISCOVER	IPV6_PMTUDISC_WANT
+opt_bool	IPV6_TRANSPARENT		IPPROTO_IPV6
+opt_int		IPV6_UNICAST_HOPS		IPPROTO_IPV6
+
+opt_str		TCP_CONGESTION			IPPROTO_TCP
+opt_bool	TCP_CORK				IPPROTO_TCP
+opt_int		TCP_DEFER_ACCEPT		IPPROTO_TCP
+opt_bool	TCP_FASTOPEN_CONNECT	IPPROTO_TCP
+opt_bool	TCP_FASTOPEN			IPPROTO_TCP
+opt_int		TCP_KEEPCNT				IPPROTO_TCP
+opt_int		TCP_KEEPIDLE			IPPROTO_TCP
+opt_int		TCP_KEEPINTVL			IPPROTO_TCP
+opt_int		TCP_LINGER2				IPPROTO_TCP
+opt_int		TCP_MAXSEG				IPPROTO_TCP
+opt_bool	TCP_NODELAY				IPPROTO_TCP
+opt_bool	TCP_QUICKACK			IPPROTO_TCP
+opt_int		TCP_SYNCNT				IPPROTO_TCP
+opt_int		TCP_USER_TIMEOUT		IPPROTO_TCP
+opt_int		TCP_WINDOW_CLAMP		IPPROTO_TCP
+
+cat <<EOF
+  {NULL, 0, 0, 0, 0}
+};
+EOF

testsuite/daemon-sockopts.test

@@ -0,0 +1,26 @@
+#!/bin/sh
+
+# The objective here is to test both --address and --sockopt
+
+. "$suitedir/rsync.fns"
+
+# This is a kitchen sink test.
+sockopts='IP_PMTUDISC_DO,TCP_CORK,TCP_DEFER_ACCEPT=1,IP_FREEBIND,IP_LOCAL_PORT_RANGE=1234,TCP_CONGESTION=bbr,TCP_QUICKACK,TCP_NODELAY,TCP_DEFER_ACCEPT=1,TCP_FASTOPEN,TCP_FASTOPEN_CONNECT'
+
+extra_config="
+socket options = ${sockopts}
+"
+build_rsyncd_conf
+
+RSYNC_CONNECT_PROG="$RSYNC --config=$conf --daemon --sockopts=${sockopts}"
+export RSYNC_CONNECT_PROG
+
+hands_setup
+
+# Build chkdir with a normal rsync and an --exclude.
+$RSYNC -av --exclude=foobar.baz "$fromdir/" "$chkdir/"
+
+checkit "'$ignore23' $RSYNC -avvvvzz --sockopts=${sockopts} '$fromdir/' localhost::test-to/" "$chkdir" "$todir"
+
+# The script would have aborted on error, so getting here means we've won.
+exit 0

testsuite/rsync.fns

@@ -387,6 +387,7 @@ exclude = ? foobar.baz
 max verbosity = 4
 $uid_setting
 $gid_setting
+$extra_config
 
 [test-from]
 	path = $fromdir