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inet: lockless IP_PKTOPTIONS implementation

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Current implementation is already lockless, because the socket
lock is released before reading socket fields.

Add missing READ_ONCE() annotations.

Note that corresponding WRITE_ONCE() are needed, the order
of the patches do not really matter.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2023-09-22 03:42:20 +00:00
committed by David S. Miller
parent 959d5c1160
commit c4480eb550
1 changed files with 37 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
net/ipv4/ip_sockglue.c
View File

@@ -1633,6 +1633,43 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
return -ENOTCONN;
goto copyval;
}
case IP_PKTOPTIONS:
{
struct msghdr msg;
if (sk->sk_type != SOCK_STREAM)
return -ENOPROTOOPT;
if (optval.is_kernel) {
msg.msg_control_is_user = false;
msg.msg_control = optval.kernel;
} else {
msg.msg_control_is_user = true;
msg.msg_control_user = optval.user;
}
msg.msg_controllen = len;
msg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0;
if (inet_test_bit(PKTINFO, sk)) {
struct in_pktinfo info;
info.ipi_addr.s_addr = READ_ONCE(inet->inet_rcv_saddr);
info.ipi_spec_dst.s_addr = READ_ONCE(inet->inet_rcv_saddr);
info.ipi_ifindex = READ_ONCE(inet->mc_index);
put_cmsg(&msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);
}
if (inet_test_bit(TTL, sk)) {
int hlim = READ_ONCE(inet->mc_ttl);
put_cmsg(&msg, SOL_IP, IP_TTL, sizeof(hlim), &hlim);
}
if (inet_test_bit(TOS, sk)) {
int tos = READ_ONCE(inet->rcv_tos);
put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos);
}
len -= msg.msg_controllen;
return copy_to_sockptr(optlen, &len, sizeof(int));
}
case IP_UNICAST_IF:
val = (__force int)htonl((__u32) READ_ONCE(inet->uc_index));
goto copyval;
@@ -1678,45 +1715,6 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
else
err = ip_get_mcast_msfilter(sk, optval, optlen, len);
goto out;
case IP_PKTOPTIONS:
{
struct msghdr msg;
sockopt_release_sock(sk);
if (sk->sk_type != SOCK_STREAM)
return -ENOPROTOOPT;
if (optval.is_kernel) {
msg.msg_control_is_user = false;
msg.msg_control = optval.kernel;
} else {
msg.msg_control_is_user = true;
msg.msg_control_user = optval.user;
}
msg.msg_controllen = len;
msg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0;
if (inet_test_bit(PKTINFO, sk)) {
struct in_pktinfo info;
info.ipi_addr.s_addr = inet->inet_rcv_saddr;
info.ipi_spec_dst.s_addr = inet->inet_rcv_saddr;
info.ipi_ifindex = inet->mc_index;
put_cmsg(&msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);
}
if (inet_test_bit(TTL, sk)) {
int hlim = READ_ONCE(inet->mc_ttl);
put_cmsg(&msg, SOL_IP, IP_TTL, sizeof(hlim), &hlim);
}
if (inet_test_bit(TOS, sk)) {
int tos = inet->rcv_tos;
put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos);
}
len -= msg.msg_controllen;
return copy_to_sockptr(optlen, &len, sizeof(int));
}
case IP_LOCAL_PORT_RANGE:
val = inet->local_port_range.hi << 16 | inet->local_port_range.lo;
break;