1 files changed, 34 insertions, 7 deletions

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index af4919792b6a..8b13881ed064 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -97,8 +97,19 @@ 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_fragsize(struct msghdr *msg, struct sk_buff *skb)
+{
+	int val;
+
+	if (IPCB(skb)->frag_max_size == 0)
+		return;
+
+	val = IPCB(skb)->frag_max_size;
+	put_cmsg(msg, SOL_IP, IP_RECVFRAGSIZE, sizeof(val), &val);
+}
+
 static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
-				  int offset)
+				  int tlen, int offset)
 {
 	__wsum csum = skb->csum;
 
@@ -106,8 +117,9 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
 		return;
 
 	if (offset != 0)
-		csum = csum_sub(csum, csum_partial(skb_transport_header(skb),
-						   offset, 0));
+		csum = csum_sub(csum,
+				csum_partial(skb_transport_header(skb) + tlen,
+					     offset, 0));
 
 	put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
 }
@@ -152,10 +164,10 @@ static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
 	put_cmsg(msg, SOL_IP, IP_ORIGDSTADDR, sizeof(sin), &sin);
 }
 
-void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb,
-			 int offset)
+void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
+			 struct sk_buff *skb, int tlen, int offset)
 {
-	struct inet_sock *inet = inet_sk(skb->sk);
+	struct inet_sock *inet = inet_sk(sk);
 	unsigned int flags = inet->cmsg_flags;
 
 	/* Ordered by supposed usage frequency */
@@ -216,7 +228,10 @@ void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb,
 	}
 
 	if (flags & IP_CMSG_CHECKSUM)
-		ip_cmsg_recv_checksum(msg, skb, offset);
+		ip_cmsg_recv_checksum(msg, skb, tlen, offset);
+
+	if (flags & IP_CMSG_RECVFRAGSIZE)
+		ip_cmsg_recv_fragsize(msg, skb);
 }
 EXPORT_SYMBOL(ip_cmsg_recv_offset);
 
@@ -613,6 +628,7 @@ static int do_ip_setsockopt(struct sock *sk, int level,
 	case IP_MULTICAST_LOOP:
 	case IP_RECVORIGDSTADDR:
 	case IP_CHECKSUM:
+	case IP_RECVFRAGSIZE:
 		if (optlen >= sizeof(int)) {
 			if (get_user(val, (int __user *) optval))
 				return -EFAULT;
@@ -725,6 +741,14 @@ static int do_ip_setsockopt(struct sock *sk, int level,
 			}
 		}
 		break;
+	case IP_RECVFRAGSIZE:
+		if (sk->sk_type != SOCK_RAW && sk->sk_type != SOCK_DGRAM)
+			goto e_inval;
+		if (val)
+			inet->cmsg_flags |= IP_CMSG_RECVFRAGSIZE;
+		else
+			inet->cmsg_flags &= ~IP_CMSG_RECVFRAGSIZE;
+		break;
 	case IP_TOS:	/* This sets both TOS and Precedence */
 		if (sk->sk_type == SOCK_STREAM) {
 			val &= ~INET_ECN_MASK;
@@ -1356,6 +1380,9 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
 	case IP_CHECKSUM:
 		val = (inet->cmsg_flags & IP_CMSG_CHECKSUM) != 0;
 		break;
+	case IP_RECVFRAGSIZE:
+		val = (inet->cmsg_flags & IP_CMSG_RECVFRAGSIZE) != 0;
+		break;
 	case IP_TOS:
 		val = inet->tos;
 		break;