From 75c65772c3d18447d62d3aca5f91b06c16cc25e4 Mon Sep 17 00:00:00 2001 From: Maxim Mikityanskiy Date: Thu, 21 Feb 2019 12:40:01 +0000 Subject: [PATCH] net/packet: Ask driver for protocol if not provided by user If a socket was created with socket(AF_PACKET, SOCK_RAW, 0), the protocol number is unavailable. Try to ask the driver to extract it from the L2 header in order for skb_try_probe_transport_header to succeed. Signed-off-by: Maxim Mikityanskiy Signed-off-by: David S. Miller --- net/packet/af_packet.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 6afd6369d19e..cac4c1a3f807 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1850,6 +1850,15 @@ oom: return 0; } +static void packet_parse_headers(struct sk_buff *skb, struct socket *sock) +{ + if (!skb->protocol && sock->type == SOCK_RAW) { + skb_reset_mac_header(skb); + skb->protocol = dev_parse_header_protocol(skb); + } + + skb_probe_transport_header(skb); +} /* * Output a raw packet to a device layer. This bypasses all the other @@ -1970,7 +1979,7 @@ retry: if (unlikely(extra_len == 4)) skb->no_fcs = 1; - skb_probe_transport_header(skb); + packet_parse_headers(skb, sock); dev_queue_xmit(skb); rcu_read_unlock(); @@ -2519,7 +2528,7 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb, len = ((to_write > len_max) ? len_max : to_write); } - skb_probe_transport_header(skb); + packet_parse_headers(skb, sock); return tp_len; } @@ -2925,7 +2934,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) virtio_net_hdr_set_proto(skb, &vnet_hdr); } - skb_probe_transport_header(skb); + packet_parse_headers(skb, sock); if (unlikely(extra_len == 4)) skb->no_fcs = 1; -- 2.39.5