4 files changed, 52 insertions, 6 deletions

diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt
index 1d6d02d6ba52..b08e27261ff9 100644
--- a/Documentation/networking/timestamping.txt
+++ b/Documentation/networking/timestamping.txt
@@ -122,7 +122,7 @@ SOF_TIMESTAMPING_RAW_HARDWARE:
 
 1.3.3 Timestamp Options
 
-The interface supports one option
+The interface supports the options
 
 SOF_TIMESTAMPING_OPT_ID:
 
@@ -145,6 +145,16 @@ SOF_TIMESTAMPING_OPT_ID:
   stream sockets, it increments with every byte.
 
 
+SOF_TIMESTAMPING_OPT_CMSG:
+
+  Support recv() cmsg for all timestamped packets. Control messages
+  are already supported unconditionally on all packets with receive
+  timestamps and on IPv6 packets with transmit timestamp. This option
+  extends them to IPv4 packets with transmit timestamp. One use case
+  is to correlate packets with their egress device, by enabling socket
+  option IP_PKTINFO simultaneously.
+
+
 1.4 Bytestream Timestamps
 
 The SO_TIMESTAMPING interface supports timestamping of bytes in a
diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h
index ff354021bb69..edbc888ceb51 100644
--- a/include/uapi/linux/net_tstamp.h
+++ b/include/uapi/linux/net_tstamp.h
@@ -23,8 +23,9 @@ enum {
         SOF_TIMESTAMPING_OPT_ID = (1<<7),
         SOF_TIMESTAMPING_TX_SCHED = (1<<8),
         SOF_TIMESTAMPING_TX_ACK = (1<<9),
+        SOF_TIMESTAMPING_OPT_CMSG = (1<<10),
 
-        SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_TX_ACK,
+        SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_CMSG,
         SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) |
                                  SOF_TIMESTAMPING_LAST
 };
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 59eba6c7a512..640f26c6a9fe 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -399,6 +399,22 @@ 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)
+{
+        struct in_pktinfo *info = PKTINFO_SKB_CB(skb);
+
+        if ((ee_origin != SO_EE_ORIGIN_TIMESTAMPING) ||
+            (!(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_CMSG)) ||
+            (!skb->dev))
+                return false;
+
+        info->ipi_spec_dst.s_addr = ip_hdr(skb)->saddr;
+        info->ipi_ifindex = skb->dev->ifindex;
+        return true;
+}
+
 /*
  *      Handle MSG_ERRQUEUE
  */
@@ -446,7 +462,9 @@ int ip_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;
         sin->sin_family = AF_UNSPEC;
-        if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP) {
+
+        if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
+            ipv4_pktinfo_prepare_errqueue(sk, skb, serr->ee.ee_origin)) {
                 struct inet_sock *inet = inet_sk(sk);
 
                 sin->sin_family = AF_INET;
@@ -1051,7 +1069,7 @@ e_inval:
 }
 
 /**
- * ipv4_pktinfo_prepare - transfert some info from rtable to skb
+ * ipv4_pktinfo_prepare - transfer some info from rtable to skb
  * @sk: socket
  * @skb: buffer
  *
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index cc1139687fd7..2464a00e36ab 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -325,6 +325,16 @@ 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)
+{
+        int ifindex = skb->dev ? skb->dev->ifindex : -1;
+
+        if (skb->protocol == htons(ETH_P_IPV6))
+                IP6CB(skb)->iif = ifindex;
+        else
+                PKTINFO_SKB_CB(skb)->ipi_ifindex = ifindex;
+}
+
 /*
  *      Handle MSG_ERRQUEUE
  */
@@ -388,8 +398,12 @@ int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
                 sin->sin6_family = AF_INET6;
                 sin->sin6_flowinfo = 0;
                 sin->sin6_port = 0;
-                if (np->rxopt.all)
+                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);
                         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)
@@ -491,7 +505,10 @@ void ip6_datagram_recv_common_ctl(struct sock *sk, struct msghdr *msg,
                         ipv6_addr_set_v4mapped(ip_hdr(skb)->daddr,
                                                &src_info.ipi6_addr);
                 }
-                put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
+
+                if (src_info.ipi6_ifindex >= 0)
+                        put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO,
+                                 sizeof(src_info), &src_info);
         }
 }