From 2606aff916854b61234bf85001be9777bab2d5f8 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Mon, 29 Jun 2020 19:06:18 -0600 Subject: [PATCH] net: ip_tunnel: add header_ops for layer 3 devices Some devices that take straight up layer 3 packets benefit from having a shared header_ops so that AF_PACKET sockets can inject packets that are recognized. This shared infrastructure will be used by other drivers that currently can't inject packets using AF_PACKET. It also exposes the parser function, as it is useful in standalone form too. Signed-off-by: Jason A. Donenfeld Acked-by: Willem de Bruijn Signed-off-by: David S. Miller --- include/net/ip_tunnels.h | 3 +++ net/ipv4/ip_tunnel_core.c | 18 ++++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h index 076e5d7db7d3..36025dea7612 100644 --- a/include/net/ip_tunnels.h +++ b/include/net/ip_tunnels.h @@ -290,6 +290,9 @@ int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[], struct ip_tunnel_parm *p, __u32 fwmark); void ip_tunnel_setup(struct net_device *dev, unsigned int net_id); +extern const struct header_ops ip_tunnel_header_ops; +__be16 ip_tunnel_parse_protocol(const struct sk_buff *skb); + struct ip_tunnel_encap_ops { size_t (*encap_hlen)(struct ip_tunnel_encap *e); int (*build_header)(struct sk_buff *skb, struct ip_tunnel_encap *e, diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c index 181b7a2a0247..f8b419e2475c 100644 --- a/net/ipv4/ip_tunnel_core.c +++ b/net/ipv4/ip_tunnel_core.c @@ -844,3 +844,21 @@ void ip_tunnel_unneed_metadata(void) static_branch_dec(&ip_tunnel_metadata_cnt); } EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata); + +/* Returns either the correct skb->protocol value, or 0 if invalid. */ +__be16 ip_tunnel_parse_protocol(const struct sk_buff *skb) +{ + if (skb_network_header(skb) >= skb->head && + (skb_network_header(skb) + sizeof(struct iphdr)) <= skb_tail_pointer(skb) && + ip_hdr(skb)->version == 4) + return htons(ETH_P_IP); + if (skb_network_header(skb) >= skb->head && + (skb_network_header(skb) + sizeof(struct ipv6hdr)) <= skb_tail_pointer(skb) && + ipv6_hdr(skb)->version == 6) + return htons(ETH_P_IPV6); + return 0; +} +EXPORT_SYMBOL(ip_tunnel_parse_protocol); + +const struct header_ops ip_tunnel_header_ops = { .parse_protocol = ip_tunnel_parse_protocol }; +EXPORT_SYMBOL(ip_tunnel_header_ops);