diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-09-12 19:02:01 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-09-15 12:33:46 +0300 |
| commit | 2da23eb07c91241d962f3ff05565065484cd8929 (patch) | |
| tree | 921417255db7f2389304c5f21aac9c828b58caa8 /net/ipv6 | |
| parent | d986f52124e062753e33b6fe303be5904a997eac (diff) | |
| download | linux-2da23eb07c91241d962f3ff05565065484cd8929.tar.xz | |
ipv6: lockless IPV6_MULTICAST_HOPS implementation
This fixes data-races around np->mcast_hops,
and make IPV6_MULTICAST_HOPS lockless.
Note that np->mcast_hops is never negative,
thus can fit an u8 field instead of s16.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/ipv6_sockglue.c | 28 | ||||
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 3 |
2 files changed, 17 insertions, 14 deletions
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 755fac85a120..5fff19a87c75 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -431,6 +431,16 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname, return -EINVAL; inet6_assign_bit(MC6_LOOP, sk, valbool); return 0; + case IPV6_MULTICAST_HOPS: + if (sk->sk_type == SOCK_STREAM) + return retv; + if (optlen < sizeof(int)) + return -EINVAL; + if (val > 255 || val < -1) + return -EINVAL; + WRITE_ONCE(np->mcast_hops, + val == -1 ? IPV6_DEFAULT_MCASTHOPS : val); + return 0; } if (needs_rtnl) rtnl_lock(); @@ -751,16 +761,6 @@ done: break; } - case IPV6_MULTICAST_HOPS: - if (sk->sk_type == SOCK_STREAM) - break; - if (optlen < sizeof(int)) - goto e_inval; - if (val > 255 || val < -1) - goto e_inval; - np->mcast_hops = (val == -1 ? IPV6_DEFAULT_MCASTHOPS : val); - retv = 0; - break; case IPV6_UNICAST_IF: { @@ -1180,7 +1180,8 @@ int do_ipv6_getsockopt(struct sock *sk, int level, int optname, put_cmsg(&msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info); } if (np->rxopt.bits.rxhlim) { - int hlim = np->mcast_hops; + int hlim = READ_ONCE(np->mcast_hops); + put_cmsg(&msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim); } if (np->rxopt.bits.rxtclass) { @@ -1197,7 +1198,8 @@ int do_ipv6_getsockopt(struct sock *sk, int level, int optname, put_cmsg(&msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info); } if (np->rxopt.bits.rxohlim) { - int hlim = np->mcast_hops; + int hlim = READ_ONCE(np->mcast_hops); + put_cmsg(&msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim); } if (np->rxopt.bits.rxflow) { @@ -1349,7 +1351,7 @@ int do_ipv6_getsockopt(struct sock *sk, int level, int optname, if (optname == IPV6_UNICAST_HOPS) val = READ_ONCE(np->hop_limit); else - val = np->mcast_hops; + val = READ_ONCE(np->mcast_hops); if (val < 0) { rcu_read_lock(); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 3a88545a265d..54db5fab318b 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1542,7 +1542,8 @@ ipv6_pktoptions: if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo) np->mcast_oif = tcp_v6_iif(opt_skb); if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) - np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit; + WRITE_ONCE(np->mcast_hops, + ipv6_hdr(opt_skb)->hop_limit); if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass) np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb)); if (np->repflow) |