[IPV4] XFRM: probe icmp type/code when sending packets via raw socket.

Signed-off-by: Masahide Nakamura <nakam@linux-ipv6.org>
Signed-off-by: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>

net/ipv4/raw.c

@@ -323,6 +323,51 @@ static int raw_send_hdrinc(struct sock *sk, void *from, int length,
 	return err; 
 }
 
+static void raw_probe_proto_opt(struct flowi *fl, struct msghdr *msg)
+{
+	struct iovec *iov;
+	u8 *type = NULL;
+	u8 *code = NULL;
+	int probed = 0;
+	int i;
+
+	if (!msg->msg_iov)
+		return;
+
+	for (i = 0; i < msg->msg_iovlen; i++) {
+		iov = &msg->msg_iov[i];
+		if (!iov)
+			continue;
+
+		switch (fl->proto) {
+		case IPPROTO_ICMP:
+			/* check if one-byte field is readable or not. */
+			if (iov->iov_base && iov->iov_len < 1)
+				break;
+
+			if (!type) {
+				type = iov->iov_base;
+				/* check if code field is readable or not. */
+				if (iov->iov_len > 1)
+					code = type + 1;
+			} else if (!code)
+				code = iov->iov_base;
+
+			if (type && code) {
+				fl->fl_icmp_type = *type;
+				fl->fl_icmp_code = *code;
+				probed = 1;
+			}
+			break;
+		default:
+			probed = 1;
+			break;
+		}
+		if (probed)
+			break;
+	}
+}
+
 static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 		       size_t len)
 {
@@ -429,6 +474,8 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 				    .proto = inet->hdrincl ? IPPROTO_RAW :
 					    		     sk->sk_protocol,
 				  };
+		raw_probe_proto_opt(&fl, msg);
+
 		err = ip_route_output_flow(&rt, &fl, sk, !(msg->msg_flags&MSG_DONTWAIT));
 	}
 	if (err)