ip: fix error queue empty skb handling

[karo-tx-linux.git] / net / ipv6 / datagram.c

diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index c215be70cac08af78953ea860c5d67cf9d3fa642..ace8daca5c8361ad37073a4eeb0f8d55c622d807 100644 (file)
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -325,14 +325,34 @@ void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
        kfree_skb(skb);
 }
 
-static void ip6_datagram_prepare_pktinfo_errqueue(struct sk_buff *skb)
+/* IPv6 supports cmsg on all origins aside from SO_EE_ORIGIN_LOCAL.
+ *
+ * At one point, excluding local errors was a quick test to identify icmp/icmp6
+ * errors. This is no longer true, but the test remained, so the v6 stack,
+ * unlike v4, also honors cmsg requests on all wifi and timestamp errors.
+ *
+ * Timestamp code paths do not initialize the fields expected by cmsg:
+ * the PKTINFO fields in skb->cb[]. Fill those in here.
+ */
+static bool ip6_datagram_support_cmsg(struct sk_buff *skb,
+                                     struct sock_exterr_skb *serr)
 {
-       int ifindex = skb->dev ? skb->dev->ifindex : -1;
+       if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
+           serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6)
+               return true;
+
+       if (serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL)
+               return false;
+
+       if (!skb->dev)
+               return false;
 
        if (skb->protocol == htons(ETH_P_IPV6))
-               IP6CB(skb)->iif = ifindex;
+               IP6CB(skb)->iif = skb->dev->ifindex;
        else
-               PKTINFO_SKB_CB(skb)->ipi_ifindex = ifindex;
+               PKTINFO_SKB_CB(skb)->ipi_ifindex = skb->dev->ifindex;
+
+       return true;
 }
 
 /*
@@ -369,7 +389,7 @@ int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
 
        serr = SKB_EXT_ERR(skb);
 
-       if (sin && skb->len) {
+       if (sin && serr->port) {
                const unsigned char *nh = skb_network_header(skb);
                sin->sin6_family = AF_INET6;
                sin->sin6_flowinfo = 0;
@@ -394,14 +414,11 @@ int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
        memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
        sin = &errhdr.offender;
        memset(sin, 0, sizeof(*sin));
-       if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL && skb->len) {
+
+       if (ip6_datagram_support_cmsg(skb, serr)) {
                sin->sin6_family = AF_INET6;
-               if (np->rxopt.all) {
-                       if (serr->ee.ee_origin != SO_EE_ORIGIN_ICMP &&
-                           serr->ee.ee_origin != SO_EE_ORIGIN_ICMP6)
-                               ip6_datagram_prepare_pktinfo_errqueue(skb);
+               if (np->rxopt.all)
                        ip6_datagram_recv_common_ctl(sk, msg, skb);
-               }
                if (skb->protocol == htons(ETH_P_IPV6)) {
                        sin->sin6_addr = ipv6_hdr(skb)->saddr;
                        if (np->rxopt.all)