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 <ja...@zx2c4.com>
---
Changes v1->v2:
- [Willem] Remove added copyright header from v1.
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);
--
2.27.0
