Commit feb2935e authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'follow-up-on-deduplicate-cookie-logic' 

Willem de Bruijn says:

====================
follow-up on deduplicate cookie logic

1/3: I came across a leftover from cookie deduplication, due to UDP
having two code paths: lockless fast path and locked cork path.

3/3: Even though the leftover was in the fast path, this prompted me
to complete coverage to the cork path.

2/3: That uncovered a subtle API inconsistency in how dontfrag is
configured. It should not be possible to switch DF mid datagram.
====================

Link: https://patch.msgid.link/20250307033620.411611-1-willemdebruijn.kernel@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 48c57a49 0922cb68

include/linux/ipv6.h

+1 −0
Original line number Diff line number Diff line
@@ -207,6 +207,7 @@ struct inet6_cork { 
	struct ipv6_txoptions *opt;

	u8 hop_limit;

	u8 tclass;

	u8 dontfrag:1;

};



/* struct ipv6_pinfo - ipv6 private area */

net/ipv6/ip6_output.c

+5 −6
Original line number Diff line number Diff line
@@ -1386,6 +1386,7 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, 
	}

	v6_cork->hop_limit = ipc6->hlimit;

	v6_cork->tclass = ipc6->tclass;

	v6_cork->dontfrag = ipc6->dontfrag;

	if (rt->dst.flags & DST_XFRM_TUNNEL)

		mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ?

		      READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
@@ -1421,7 +1422,7 @@ static int __ip6_append_data(struct sock *sk, 
			     int getfrag(void *from, char *to, int offset,

					 int len, int odd, struct sk_buff *skb),

			     void *from, size_t length, int transhdrlen,

			     unsigned int flags, struct ipcm6_cookie *ipc6)

			     unsigned int flags)

{

	struct sk_buff *skb, *skb_prev = NULL;

	struct inet_cork *cork = &cork_full->base;
@@ -1475,7 +1476,7 @@ static int __ip6_append_data(struct sock *sk, 
	if (headersize + transhdrlen > mtu)

		goto emsgsize;



	if (cork->length + length > mtu - headersize && ipc6->dontfrag &&

	if (cork->length + length > mtu - headersize && v6_cork->dontfrag &&

	    (sk->sk_protocol == IPPROTO_UDP ||

	     sk->sk_protocol == IPPROTO_ICMPV6 ||

	     sk->sk_protocol == IPPROTO_RAW)) {
@@ -1855,7 +1856,7 @@ int ip6_append_data(struct sock *sk, 


	return __ip6_append_data(sk, &sk->sk_write_queue, &inet->cork,

				 &np->cork, sk_page_frag(sk), getfrag,

				 from, length, transhdrlen, flags, ipc6);

				 from, length, transhdrlen, flags);

}

EXPORT_SYMBOL_GPL(ip6_append_data);
@@ -2054,13 +2055,11 @@ struct sk_buff *ip6_make_skb(struct sock *sk, 
		ip6_cork_release(cork, &v6_cork);

		return ERR_PTR(err);

	}

	if (ipc6->dontfrag < 0)

		ipc6->dontfrag = inet6_test_bit(DONTFRAG, sk);



	err = __ip6_append_data(sk, &queue, cork, &v6_cork,

				&current->task_frag, getfrag, from,

				length + exthdrlen, transhdrlen + exthdrlen,

				flags, ipc6);

				flags);

	if (err) {

		__ip6_flush_pending_frames(sk, &queue, cork, &v6_cork);

		return ERR_PTR(err);

tools/testing/selftests/net/cmsg_ip.sh

+7 −4
Original line number Diff line number Diff line
@@ -50,8 +50,9 @@ check_result() { 
# IPV6_DONTFRAG

for ovr in setsock cmsg both diff; do

    for df in 0 1; do

	for p in u i r; do

	for p in u U i r; do

	    [ $p == "u" ] && prot=UDP

	    [ $p == "U" ] && prot=UDP

	    [ $p == "i" ] && prot=ICMP

	    [ $p == "r" ] && prot=RAW
@@ -81,8 +82,9 @@ test_dscp() { 
    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

	for p in u U i r; do

	    [ $p == "u" ] && prot=UDP

	    [ $p == "U" ] && prot=UDP

	    [ $p == "i" ] && prot=ICMP

	    [ $p == "r" ] && prot=RAW
@@ -134,8 +136,9 @@ test_ttl_hoplimit() { 
    local -r LIM=4



    for ovr in setsock cmsg both diff; do

	for p in u i r; do

	for p in u U i r; do

	    [ $p == "u" ] && prot=UDP

	    [ $p == "U" ] && prot=UDP

	    [ $p == "i" ] && prot=ICMP

	    [ $p == "r" ] && prot=RAW
@@ -166,7 +169,7 @@ test_ttl_hoplimit -4 $TGT4 ttl 
test_ttl_hoplimit -6 $TGT6 hlim



# IPV6 exthdr

for p in u i r; do

for p in u U i r; do

    # Very basic "does it crash" test

    for h in h d r; do

	$NSEXE ./cmsg_sender -p $p -6 -H $h $TGT6 1234

tools/testing/selftests/net/cmsg_sender.c

+19 −5
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ enum { 
	ERN_RECVERR,

	ERN_CMSG_RD,

	ERN_CMSG_RCV,

	ERN_SEND_MORE,

};



struct option_cmsg_u32 {
@@ -46,6 +47,7 @@ struct options { 
	const char *service;

	unsigned int size;

	unsigned int num_pkt;

	bool msg_more;

	struct {

		unsigned int mark;

		unsigned int dontfrag;
@@ -94,7 +96,8 @@ static void __attribute__((noreturn)) cs_usage(const char *bin) 
	       "\t\t-S      send() size\n"

	       "\t\t-4/-6   Force IPv4 / IPv6 only\n"

	       "\t\t-p prot Socket protocol\n"

	       "\t\t        (u = UDP (default); i = ICMP; r = RAW)\n"

	       "\t\t        (u = UDP (default); i = ICMP; r = RAW;\n"

	       "\t\t         U = UDP with MSG_MORE)\n"

	       "\n"

	       "\t\t-m val  Set SO_MARK with given value\n"

	       "\t\t-M val  Set SO_MARK via setsockopt\n"
@@ -109,8 +112,8 @@ static void __attribute__((noreturn)) cs_usage(const char *bin) 
	       "\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)"

	       "");

	       "\t\t        (h = HOP; d = DST; r = RTDST)\n"

	       "\n");

	exit(ERN_HELP);

}
@@ -133,8 +136,11 @@ static void cs_parse_args(int argc, char *argv[]) 
			opt.sock.family = AF_INET6;

			break;

		case 'p':

			if (*optarg == 'u' || *optarg == 'U') {

			if (*optarg == 'u') {

				opt.sock.proto = IPPROTO_UDP;

			} else if (*optarg == 'U') {

				opt.sock.proto = IPPROTO_UDP;

				opt.msg_more = true;

			} else if (*optarg == 'i' || *optarg == 'I') {

				opt.sock.proto = IPPROTO_ICMP;

			} else if (*optarg == 'r') {
@@ -531,7 +537,7 @@ int main(int argc, char *argv[]) 
	cs_write_cmsg(fd, &msg, cbuf, sizeof(cbuf));



	for (i = 0; i < opt.num_pkt; i++) {

		err = sendmsg(fd, &msg, 0);

		err = sendmsg(fd, &msg, opt.msg_more ? MSG_MORE : 0);

		if (err < 0) {

			if (!opt.silent_send)

				fprintf(stderr, "send failed: %s\n", strerror(errno));
@@ -542,6 +548,14 @@ int main(int argc, char *argv[]) 
			err = ERN_SEND_SHORT;

			goto err_out;

		}

		if (opt.msg_more) {

			err = write(fd, NULL, 0);

			if (err < 0) {

				fprintf(stderr, "send more: %s\n", strerror(errno));

				err = ERN_SEND_MORE;

				goto err_out;

			}

		}

	}

	err = ERN_SUCCESS;