ip: fix error queue empty skb handling

[karo-tx-linux.git] / net / ipv4 / ip_sockglue.c

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 31d8c71986b40e28e5c84f5e62d474a639d3bf91..5cd99271d3a6a07c17a915fddde7a5a0c8a86618 100644 (file)
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -432,17 +432,32 @@ void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 port, u32 inf
                kfree_skb(skb);
 }
 
-static bool ipv4_pktinfo_prepare_errqueue(const struct sock *sk,
-                                         const struct sk_buff *skb,
-                                         int ee_origin)
+/* IPv4 supports cmsg on all imcp errors and some timestamps
+ *
+ * Timestamp code paths do not initialize the fields expected by cmsg:
+ * the PKTINFO fields in skb->cb[]. Fill those in here.
+ */
+static bool ipv4_datagram_support_cmsg(const struct sock *sk,
+                                      struct sk_buff *skb,
+                                      int ee_origin)
 {
-       struct in_pktinfo *info = PKTINFO_SKB_CB(skb);
+       struct in_pktinfo *info;
+
+       if (ee_origin == SO_EE_ORIGIN_ICMP)
+               return true;
 
-       if ((ee_origin != SO_EE_ORIGIN_TIMESTAMPING) ||
-           (!(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_CMSG)) ||
+       if (ee_origin == SO_EE_ORIGIN_LOCAL)
+               return false;
+
+       /* Support IP_PKTINFO on tstamp packets if requested, to correlate
+        * timestamp with egress dev. Not possible for packets without dev
+        * or without payload (SOF_TIMESTAMPING_OPT_TSONLY).
+        */
+       if ((!(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_CMSG)) ||
            (!skb->dev))
                return false;
 
+       info = PKTINFO_SKB_CB(skb);
        info->ipi_spec_dst.s_addr = ip_hdr(skb)->saddr;
        info->ipi_ifindex = skb->dev->ifindex;
        return true;
@@ -483,7 +498,7 @@ int ip_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) {
                sin->sin_family = AF_INET;
                sin->sin_addr.s_addr = *(__be32 *)(skb_network_header(skb) +
                                                   serr->addr_offset);
@@ -496,9 +511,7 @@ int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
        sin = &errhdr.offender;
        memset(sin, 0, sizeof(*sin));
 
-       if (skb->len &&
-           (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
-            ipv4_pktinfo_prepare_errqueue(sk, skb, serr->ee.ee_origin))) {
+       if (ipv4_datagram_support_cmsg(sk, skb, serr->ee.ee_origin)) {
                sin->sin_family = AF_INET;
                sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
                if (inet_sk(sk)->cmsg_flags)