From 829ae9d611651467fe6cd7be834bd33ca6b28dfe Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Sun, 30 Nov 2014 22:22:34 -0500 Subject: [PATCH] net-timestamp: allow reading recv cmsg on errqueue with origin tstamp Allow reading of timestamps and cmsg at the same time on all relevant socket families. One use is to correlate timestamps with egress device, by asking for cmsg IP_PKTINFO. on AF_INET sockets, call the relevant function (ip_cmsg_recv). To avoid changing legacy expectations, only do so if the caller sets a new timestamping flag SOF_TIMESTAMPING_OPT_CMSG. on AF_INET6 sockets, IPV6_PKTINFO and all other recv cmsg are already returned for all origins. only change is to set ifindex, which is not initialized for all error origins. In both cases, only generate the pktinfo message if an ifindex is known. This is not the case for ACK timestamps. The difference between the protocol families is probably a historical accident as a result of the different conditions for generating cmsg in the relevant ip(v6)_recv_error function: ipv4: if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP) { ipv6: if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) { At one time, this was the same test bar for the ICMP/ICMP6 distinction. This is no longer true. Signed-off-by: Willem de Bruijn ---- Changes v1 -> v2 large rewrite - integrate with existing pktinfo cmsg generation code - on ipv4: only send with new flag, to maintain legacy behavior - on ipv6: send at most a single pktinfo cmsg - on ipv6: initialize fields if not yet initialized The recv cmsg interfaces are also relevant to the discussion of whether looping packet headers is problematic. For v6, cmsgs that identify many headers are already returned. This patch expands that to v4. If it sounds reasonable, I will follow with patches 1. request timestamps without payload with SOF_TIMESTAMPING_OPT_TSONLY (http://patchwork.ozlabs.org/patch/366967/) 2. sysctl to conditionally drop all timestamps that have payload or cmsg from users without CAP_NET_RAW. Signed-off-by: David S. Miller --- Documentation/networking/timestamping.txt | 12 +++++++++++- include/uapi/linux/net_tstamp.h | 3 ++- net/ipv4/ip_sockglue.c | 22 ++++++++++++++++++++-- net/ipv6/datagram.c | 21 +++++++++++++++++++-- 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); } } -- 2.20.1