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-rw-r--r--include/net/inet_sock.h1
-rw-r--r--include/uapi/linux/in.h1
-rw-r--r--net/ipv4/ip_sockglue.c41
-rw-r--r--net/ipv4/udp.c2
4 files changed, 43 insertions, 2 deletions
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 605ca421d5ab..eb16c7beed1e 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -203,6 +203,7 @@ struct inet_sock {
#define IP_CMSG_RETOPTS BIT(4)
#define IP_CMSG_PASSSEC BIT(5)
#define IP_CMSG_ORIGDSTADDR BIT(6)
+#define IP_CMSG_CHECKSUM BIT(7)
static inline struct inet_sock *inet_sk(const struct sock *sk)
{
diff --git a/include/uapi/linux/in.h b/include/uapi/linux/in.h
index c33a65e3d62c..589ced069e8a 100644
--- a/include/uapi/linux/in.h
+++ b/include/uapi/linux/in.h
@@ -109,6 +109,7 @@ struct in_addr {
#define IP_MINTTL 21
#define IP_NODEFRAG 22
+#define IP_CHECKSUM 23
/* IP_MTU_DISCOVER values */
#define IP_PMTUDISC_DONT 0 /* Never send DF frames */
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 513d506ffebb..a317797b3cd0 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -37,6 +37,7 @@
#include <net/route.h>
#include <net/xfrm.h>
#include <net/compat.h>
+#include <net/checksum.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/transp_v6.h>
#endif
@@ -96,6 +97,20 @@ static void ip_cmsg_recv_retopts(struct msghdr *msg, struct sk_buff *skb)
put_cmsg(msg, SOL_IP, IP_RETOPTS, opt->optlen, opt->__data);
}
+static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
+ int offset)
+{
+ __wsum csum = skb->csum;
+
+ if (skb->ip_summed != CHECKSUM_COMPLETE)
+ return;
+
+ if (offset != 0)
+ csum = csum_sub(csum, csum_partial(skb->data, offset, 0));
+
+ put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
+}
+
static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
{
char *secdata;
@@ -191,9 +206,16 @@ void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb,
return;
}
- if (flags & IP_CMSG_ORIGDSTADDR)
+ if (flags & IP_CMSG_ORIGDSTADDR) {
ip_cmsg_recv_dstaddr(msg, skb);
+ flags &= ~IP_CMSG_ORIGDSTADDR;
+ if (!flags)
+ return;
+ }
+
+ if (flags & IP_CMSG_CHECKSUM)
+ ip_cmsg_recv_checksum(msg, skb, offset);
}
EXPORT_SYMBOL(ip_cmsg_recv_offset);
@@ -533,6 +555,7 @@ static int do_ip_setsockopt(struct sock *sk, int level,
case IP_MULTICAST_ALL:
case IP_MULTICAST_LOOP:
case IP_RECVORIGDSTADDR:
+ case IP_CHECKSUM:
if (optlen >= sizeof(int)) {
if (get_user(val, (int __user *) optval))
return -EFAULT;
@@ -630,6 +653,19 @@ static int do_ip_setsockopt(struct sock *sk, int level,
else
inet->cmsg_flags &= ~IP_CMSG_ORIGDSTADDR;
break;
+ case IP_CHECKSUM:
+ if (val) {
+ if (!(inet->cmsg_flags & IP_CMSG_CHECKSUM)) {
+ inet_inc_convert_csum(sk);
+ inet->cmsg_flags |= IP_CMSG_CHECKSUM;
+ }
+ } else {
+ if (inet->cmsg_flags & IP_CMSG_CHECKSUM) {
+ inet_dec_convert_csum(sk);
+ inet->cmsg_flags &= ~IP_CMSG_CHECKSUM;
+ }
+ }
+ break;
case IP_TOS: /* This sets both TOS and Precedence */
if (sk->sk_type == SOCK_STREAM) {
val &= ~INET_ECN_MASK;
@@ -1233,6 +1269,9 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
case IP_RECVORIGDSTADDR:
val = (inet->cmsg_flags & IP_CMSG_ORIGDSTADDR) != 0;
break;
+ case IP_CHECKSUM:
+ val = (inet->cmsg_flags & IP_CMSG_CHECKSUM) != 0;
+ break;
case IP_TOS:
val = inet->tos;
break;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 53358d88f110..97ef1f8b7be8 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1329,7 +1329,7 @@ try_again:
*addr_len = sizeof(*sin);
}
if (inet->cmsg_flags)
- ip_cmsg_recv(msg, skb);
+ ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr));
err = copied;
if (flags & MSG_TRUNC)