[PATCH net-next 2/2] selftests/net: expand cmsg_ipv6.sh with ipv4

25 Feb 2025

From: Willem de Bruijn willemb@google.com
Expand IPV6_TCLASS to also cover IP_TOS.
Expand IPV6_HOPLIMIT to also cover IP_TTL.
Expand csmg_sender.c to allow setting IPv4 setsockopts.
Also rename struct v6 to cmsg to match its expanded scope.
Don't bother updating all occurrences of tclass and hoplimit.
Rename cmsg_ipv6.sh to cmsg_ip.sh to match the expanded scope.
Be careful around the subtle API difference between TCLASS and TOS.
IP_TOS includes ECN bits. Add a test to verify that these are masked
when making routing decisions.
Diff is more concise with --word-diff
Signed-off-by: Willem de Bruijn willemb@google.com
---
 tools/testing/selftests/net/Makefile          |  2 +-
 .../net/{cmsg_ipv6.sh => cmsg_ip.sh}          | 59 ++++++++----
 tools/testing/selftests/net/cmsg_sender.c     | 90 +++++++++++--------
 3 files changed, 96 insertions(+), 55 deletions(-)
 rename tools/testing/selftests/net/{cmsg_ipv6.sh => cmsg_ip.sh} (65%)

diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index aeb96c085614..2e16ce6d28e4 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -34,7 +34,7 @@ TEST_PROGS += gre_gso.sh
 TEST_PROGS += cmsg_so_mark.sh
 TEST_PROGS += cmsg_so_priority.sh
 TEST_PROGS += test_so_rcv.sh
-TEST_PROGS += cmsg_time.sh cmsg_ipv6.sh
+TEST_PROGS += cmsg_time.sh cmsg_ip.sh
 TEST_PROGS += netns-name.sh
 TEST_PROGS += link_netns.py
 TEST_PROGS += nl_netdev.py
diff --git a/tools/testing/selftests/net/cmsg_ipv6.sh b/tools/testing/selftests/net/cmsg_ip.sh
similarity index 65%
rename from tools/testing/selftests/net/cmsg_ipv6.sh
rename to tools/testing/selftests/net/cmsg_ip.sh
index 51132c26e9b5..2a52520aca32 100755
--- a/tools/testing/selftests/net/cmsg_ipv6.sh
+++ b/tools/testing/selftests/net/cmsg_ip.sh
@@ -3,6 +3,8 @@
source lib.sh
+IP4=172.16.0.1/24
+TGT4=172.16.0.2
 IP6=2001:db8:1::1/64
 TGT6=2001:db8:1::2
 TMPF=$(mktemp --suffix ".pcap")
@@ -30,6 +32,7 @@ $NSEXE sysctl -w net.ipv4.ping_group_range='0 2147483647' > /dev/null
 # Connectivity
 ip -netns $NS link add type dummy
 ip -netns $NS link set dev dummy0 up
+ip -netns $NS addr add $IP4 dev dummy0
 ip -netns $NS addr add $IP6 dev dummy0
# Test
@@ -63,14 +66,19 @@ for ovr in setsock cmsg both diff; do
     done
 done
-# IPV6_TCLASS
+# IP_TOS + IPV6_TCLASS
test_dscp() {
+    local -r IPVER=$1
+    local -r TGT=$2
+    local -r MATCH=$3
+
     local -r TOS=0x10
     local -r TOS2=0x20
+    local -r ECN=0x3
-    ip -6 -netns $NS rule add tos $TOS lookup 300
-    ip -6 -netns $NS route add table 300 prohibit any
+    ip $IPVER -netns $NS rule add tos $TOS lookup 300
+    ip $IPVER -netns $NS route add table 300 prohibit any
for ovr in setsock cmsg both diff; do
    for p in u i r; do
@@ -87,30 +95,42 @@ test_dscp() {
        BG=$!
        sleep 0.05
-	    $NSEXE ./cmsg_sender -6 -p $p $m $((TOS2)) $TGT6 1234
-	    check_result $? 0 "TCLASS $prot $ovr - pass"
+	    $NSEXE ./cmsg_sender $IPVER -p $p $m $((TOS2)) $TGT 1234
+	    check_result $? 0 "$MATCH $prot $ovr - pass"
while [ -d /proc/$BG ]; do
-	        $NSEXE ./cmsg_sender -6 -p $p $m $((TOS2)) $TGT6 1234
+	        $NSEXE ./cmsg_sender $IPVER -p $p $m $((TOS2)) $TGT 1234
        done
-	    tcpdump -r $TMPF -v 2>&1 | grep "class $TOS2" >> /dev/null
-	    check_result $? 0 "TCLASS $prot $ovr - packet data"
+	    tcpdump -r $TMPF -v 2>&1 | grep "$MATCH $TOS2" >> /dev/null
+	    check_result $? 0 "$MATCH $prot $ovr - packet data"
        rm $TMPF
[ $ovr == "both" ]    && m="-C $((TOS )) -c"
        [ $ovr == "diff" ]    && m="-C $((TOS2)) -c"
-	    $NSEXE ./cmsg_sender -6 -p $p $m $((TOS)) -s $TGT6 1234
-	    check_result $? 1 "TCLASS $prot $ovr - rejection"
+	    # Match prohibit rule: expect failure
+	    $NSEXE ./cmsg_sender $IPVER -p $p $m $((TOS)) -s $TGT 1234
+	    check_result $? 1 "$MATCH $prot $ovr - rejection"
+
+	    # Match prohibit rule: IPv4 masks ECN: expect failure
+	    if [[ "$IPVER" == "-4" ]]; then
+		$NSEXE ./cmsg_sender $IPVER -p $p $m "$((TOS | ECN))" -s $TGT 1234
+		check_result $? 1 "$MATCH $prot $ovr - rejection (ECN)"
+	    fi
    done
     done
 }
-test_dscp
+test_dscp -4 $TGT4 tos
+test_dscp -6 $TGT6 class
+
+# IP_TTL + IPV6_HOPLIMIT
+test_ttl_hoplimit() {
+    local -r IPVER=$1
+    local -r TGT=$2
+    local -r MATCH=$3
-# IPV6_HOPLIMIT
-test_hoplimit() {
     local -r LIM=4
for ovr in setsock cmsg both diff; do
@@ -128,21 +148,22 @@ test_hoplimit() {
        BG=$!
        sleep 0.05
-	    $NSEXE ./cmsg_sender -6 -p $p $m $LIM $TGT6 1234
-	    check_result $? 0 "HOPLIMIT $prot $ovr - pass"
+	    $NSEXE ./cmsg_sender $IPVER -p $p $m $LIM $TGT 1234
+	    check_result $? 0 "$MATCH $prot $ovr - pass"
while [ -d /proc/$BG ]; do
-	        $NSEXE ./cmsg_sender -6 -p $p $m $LIM $TGT6 1234
+		$NSEXE ./cmsg_sender $IPVER -p $p $m $LIM $TGT 1234
        done
-	    tcpdump -r $TMPF -v 2>&1 | grep "hlim $LIM[^0-9]" >> /dev/null
-	    check_result $? 0 "HOPLIMIT $prot $ovr - packet data"
+	    tcpdump -r $TMPF -v 2>&1 | grep "$MATCH $LIM[^0-9]" >> /dev/null
+	    check_result $? 0 "$MATCH $prot $ovr - packet data"
        rm $TMPF
    done
     done
 }
-test_hoplimit
+test_ttl_hoplimit -4 $TGT4 ttl
+test_ttl_hoplimit -6 $TGT6 hlim
# IPV6 exthdr
 for p in u i r; do
diff --git a/tools/testing/selftests/net/cmsg_sender.c b/tools/testing/selftests/net/cmsg_sender.c
index bc314382e4e1..19bd8499031b 100644
--- a/tools/testing/selftests/net/cmsg_sender.c
+++ b/tools/testing/selftests/net/cmsg_sender.c
@@ -72,7 +72,7 @@ struct options {
    	struct option_cmsg_u32 tclass;
    	struct option_cmsg_u32 hlimit;
    	struct option_cmsg_u32 exthdr;
-	} v6;
+	} cmsg;
 } opt = {
    .size = 13,
    .num_pkt = 1,
@@ -104,10 +104,10 @@ static void __attribute__((noreturn)) cs_usage(const char *bin)
           "\t\t-t      Enable time stamp reporting\n"
           "\t\t-f val  Set don't fragment via cmsg\n"
           "\t\t-F val  Set don't fragment via setsockopt\n"
-	       "\t\t-c val  Set TCLASS via cmsg\n"
-	       "\t\t-C val  Set TCLASS via setsockopt\n"
-	       "\t\t-l val  Set HOPLIMIT via cmsg\n"
-	       "\t\t-L val  Set HOPLIMIT via setsockopt\n"
+	       "\t\t-c val  Set TOS/TCLASS via cmsg\n"
+	       "\t\t-C val  Set TOS/TCLASS via setsockopt\n"
+	       "\t\t-l val  Set TTL/HOPLIMIT via cmsg\n"
+	       "\t\t-L val  Set TTL/HOPLIMIT via setsockopt\n"
           "\t\t-H type Add an IPv6 header option\n"
           "\t\t        (h = HOP; d = DST; r = RTDST)"
           "");
@@ -169,37 +169,37 @@ static void cs_parse_args(int argc, char *argv[])
    		opt.ts.ena = true;
    		break;
    	case 'f':
-			opt.v6.dontfrag.ena = true;
-			opt.v6.dontfrag.val = atoi(optarg);
+			opt.cmsg.dontfrag.ena = true;
+			opt.cmsg.dontfrag.val = atoi(optarg);
    		break;
    	case 'F':
    		opt.sockopt.dontfrag = atoi(optarg);
    		break;
    	case 'c':
-			opt.v6.tclass.ena = true;
-			opt.v6.tclass.val = atoi(optarg);
+			opt.cmsg.tclass.ena = true;
+			opt.cmsg.tclass.val = atoi(optarg);
    		break;
    	case 'C':
    		opt.sockopt.tclass = atoi(optarg);
    		break;
    	case 'l':
-			opt.v6.hlimit.ena = true;
-			opt.v6.hlimit.val = atoi(optarg);
+			opt.cmsg.hlimit.ena = true;
+			opt.cmsg.hlimit.val = atoi(optarg);
    		break;
    	case 'L':
    		opt.sockopt.hlimit = atoi(optarg);
    		break;
    	case 'H':
-			opt.v6.exthdr.ena = true;
+			opt.cmsg.exthdr.ena = true;
    		switch (optarg[0]) {
    		case 'h':
-				opt.v6.exthdr.val = IPV6_HOPOPTS;
+				opt.cmsg.exthdr.val = IPV6_HOPOPTS;
    			break;
    		case 'd':
-				opt.v6.exthdr.val = IPV6_DSTOPTS;
+				opt.cmsg.exthdr.val = IPV6_DSTOPTS;
    			break;
    		case 'r':
-				opt.v6.exthdr.val = IPV6_RTHDRDSTOPTS;
+				opt.cmsg.exthdr.val = IPV6_RTHDRDSTOPTS;
    			break;
    		default:
    			printf("Error: hdr type: %s\n", optarg);
@@ -261,12 +261,20 @@ cs_write_cmsg(int fd, struct msghdr *msg, char *cbuf, size_t cbuf_sz)
    		  SOL_SOCKET, SO_MARK, &opt.mark);
    ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
    		  SOL_SOCKET, SO_PRIORITY, &opt.priority);
-	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
-			  SOL_IPV6, IPV6_DONTFRAG, &opt.v6.dontfrag);
-	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
-			  SOL_IPV6, IPV6_TCLASS, &opt.v6.tclass);
-	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
-			  SOL_IPV6, IPV6_HOPLIMIT, &opt.v6.hlimit);
+
+	if (opt.sock.family == AF_INET) {
+		ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
+				  SOL_IP, IP_TOS, &opt.cmsg.tclass);
+		ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
+				  SOL_IP, IP_TTL, &opt.cmsg.hlimit);
+	} else {
+		ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
+				  SOL_IPV6, IPV6_DONTFRAG, &opt.cmsg.dontfrag);
+		ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
+				  SOL_IPV6, IPV6_TCLASS, &opt.cmsg.tclass);
+		ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
+				  SOL_IPV6, IPV6_HOPLIMIT, &opt.cmsg.hlimit);
+	}
if (opt.txtime.ena) {
    	__u64 txtime;
@@ -297,14 +305,14 @@ cs_write_cmsg(int fd, struct msghdr *msg, char *cbuf, size_t cbuf_sz)
    	*(__u32 *)CMSG_DATA(cmsg) = SOF_TIMESTAMPING_TX_SCHED |
    				    SOF_TIMESTAMPING_TX_SOFTWARE;
    }
-	if (opt.v6.exthdr.ena) {
+	if (opt.cmsg.exthdr.ena) {
    	cmsg = (struct cmsghdr *)(cbuf + cmsg_len);
    	cmsg_len += CMSG_SPACE(8);
    	if (cbuf_sz < cmsg_len)
    		error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");
cmsg->cmsg_level = SOL_IPV6;
-		cmsg->cmsg_type = opt.v6.exthdr.val;
+		cmsg->cmsg_type = opt.cmsg.exthdr.val;
    	cmsg->cmsg_len = CMSG_LEN(8);
    	*(__u64 *)CMSG_DATA(cmsg) = 0;
    }
@@ -405,23 +413,35 @@ static void ca_set_sockopts(int fd)
        setsockopt(fd, SOL_SOCKET, SO_MARK,
    	       &opt.sockopt.mark, sizeof(opt.sockopt.mark)))
    	error(ERN_SOCKOPT, errno, "setsockopt SO_MARK");
-	if (opt.sockopt.dontfrag &&
-	    setsockopt(fd, SOL_IPV6, IPV6_DONTFRAG,
-		       &opt.sockopt.dontfrag, sizeof(opt.sockopt.dontfrag)))
-		error(ERN_SOCKOPT, errno, "setsockopt IPV6_DONTFRAG");
-	if (opt.sockopt.tclass &&
-	    setsockopt(fd, SOL_IPV6, IPV6_TCLASS,
-		       &opt.sockopt.tclass, sizeof(opt.sockopt.tclass)))
-		error(ERN_SOCKOPT, errno, "setsockopt IPV6_TCLASS");
-	if (opt.sockopt.hlimit &&
-	    setsockopt(fd, SOL_IPV6, IPV6_UNICAST_HOPS,
-		       &opt.sockopt.hlimit, sizeof(opt.sockopt.hlimit)))
-		error(ERN_SOCKOPT, errno, "setsockopt IPV6_HOPLIMIT");
    if (opt.sockopt.priority &&
        setsockopt(fd, SOL_SOCKET, SO_PRIORITY,
    	       &opt.sockopt.priority, sizeof(opt.sockopt.priority)))
    	error(ERN_SOCKOPT, errno, "setsockopt SO_PRIORITY");
+	if (opt.sock.family == AF_INET) {
+		if (opt.sockopt.tclass &&
+		    setsockopt(fd, SOL_IP, IP_TOS,
+			       &opt.sockopt.tclass, sizeof(opt.sockopt.tclass)))
+			error(ERN_SOCKOPT, errno, "setsockopt IP_TOS");
+		if (opt.sockopt.hlimit &&
+		    setsockopt(fd, SOL_IP, IP_TTL,
+			       &opt.sockopt.hlimit, sizeof(opt.sockopt.hlimit)))
+			error(ERN_SOCKOPT, errno, "setsockopt IP_TTL");
+	} else {
+		if (opt.sockopt.dontfrag &&
+		    setsockopt(fd, SOL_IPV6, IPV6_DONTFRAG,
+			       &opt.sockopt.dontfrag, sizeof(opt.sockopt.dontfrag)))
+			error(ERN_SOCKOPT, errno, "setsockopt IPV6_DONTFRAG");
+		if (opt.sockopt.tclass &&
+		    setsockopt(fd, SOL_IPV6, IPV6_TCLASS,
+			       &opt.sockopt.tclass, sizeof(opt.sockopt.tclass)))
+			error(ERN_SOCKOPT, errno, "setsockopt IPV6_TCLASS");
+		if (opt.sockopt.hlimit &&
+		    setsockopt(fd, SOL_IPV6, IPV6_UNICAST_HOPS,
+			       &opt.sockopt.hlimit, sizeof(opt.sockopt.hlimit)))
+			error(ERN_SOCKOPT, errno, "setsockopt IPV6_HOPLIMIT");
+	}
+
    if (opt.txtime.ena) {
    	struct sock_txtime so_txtime = {
    		.clockid = CLOCK_MONOTONIC,
-- 
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[PATCH net-next 2/2] selftests/net: expand cmsg_ipv6.sh with ipv4