xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

selftests/bpf: expand test_tc_tunnel with SIT encap

Browse Source 
So far, all BPF tc tunnel testcases encapsulate in the same network
protocol. Add an encap testcase that requires updating skb->protocol.

The 6in4 tunnel encapsulates an IPv6 packet inside an IPv4 tunnel.
Verify that bpf_skb_net_grow correctly updates skb->protocol to
select the right protocol handler in __netif_receive_skb_core.

The BPF program should also manually update the link layer header to
encode the right network protocol.

Changes v1->v2
  - improve documentation of non-obvious logic

Signed-off-by: Willem de Bruijn <willemb@google.com>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Willem de Bruijn
2019-04-23 14:43:49 -04:00
committed by Daniel Borkmann
parent 1b00e0dfe7
commit f6ad6accaa
3 changed files with 80 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

64
tools/testing/selftests/bpf/progs/test_tc_tunnel.c
View File

@@ -77,17 +77,52 @@ static __always_inline int encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
struct v4hdr h_outer;
struct tcphdr tcph;
int olen, l2_len;
int tcp_off;
__u64 flags;
if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
sizeof(iph_inner)) < 0)
return TC_ACT_OK;
/* Most tests encapsulate a packet into a tunnel with the same
* network protocol, and derive the outer header fields from
* the inner header.
*
* The 6in4 case tests different inner and outer protocols. As
* the inner is ipv6, but the outer expects an ipv4 header as
* input, manually build a struct iphdr based on the ipv6hdr.
*/
if (encap_proto == IPPROTO_IPV6) {
const __u32 saddr = (192 << 24) | (168 << 16) | (1 << 8) | 1;
const __u32 daddr = (192 << 24) | (168 << 16) | (1 << 8) | 2;
struct ipv6hdr iph6_inner;
/* Read the IPv6 header */
if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph6_inner,
sizeof(iph6_inner)) < 0)
return TC_ACT_OK;
/* Derive the IPv4 header fields from the IPv6 header */
memset(&iph_inner, 0, sizeof(iph_inner));
iph_inner.version = 4;
iph_inner.ihl = 5;
iph_inner.tot_len = bpf_htons(sizeof(iph6_inner) +
bpf_ntohs(iph6_inner.payload_len));
iph_inner.ttl = iph6_inner.hop_limit - 1;
iph_inner.protocol = iph6_inner.nexthdr;
iph_inner.saddr = __bpf_constant_htonl(saddr);
iph_inner.daddr = __bpf_constant_htonl(daddr);
tcp_off = sizeof(iph6_inner);
} else {
if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
sizeof(iph_inner)) < 0)
return TC_ACT_OK;
tcp_off = sizeof(iph_inner);
}
/* filter only packets we want */
if (iph_inner.ihl != 5 || iph_inner.protocol != IPPROTO_TCP)
return TC_ACT_OK;
if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(iph_inner),
if (bpf_skb_load_bytes(skb, ETH_HLEN + tcp_off,
&tcph, sizeof(tcph)) < 0)
return TC_ACT_OK;
@@ -129,6 +164,7 @@ static __always_inline int encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
l2_len);
break;
case IPPROTO_IPIP:
case IPPROTO_IPV6:
break;
default:
return TC_ACT_OK;
@@ -164,6 +200,17 @@ static __always_inline int encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
BPF_F_INVALIDATE_HASH) < 0)
return TC_ACT_SHOT;
/* if changing outer proto type, update eth->h_proto */
if (encap_proto == IPPROTO_IPV6) {
struct ethhdr eth;
if (bpf_skb_load_bytes(skb, 0, &eth, sizeof(eth)) < 0)
return TC_ACT_SHOT;
eth.h_proto = bpf_htons(ETH_P_IP);
if (bpf_skb_store_bytes(skb, 0, &eth, sizeof(eth), 0) < 0)
return TC_ACT_SHOT;
}
return TC_ACT_OK;
}
@@ -325,6 +372,15 @@ int __encap_udp_eth(struct __sk_buff *skb)
return TC_ACT_OK;
}
SEC("encap_sit_none")
int __encap_sit_none(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
return encap_ipv4(skb, IPPROTO_IPV6, ETH_P_IP);
else
return TC_ACT_OK;
}
SEC("encap_ip6tnl_none")
int __encap_ip6tnl_none(struct __sk_buff *skb)
{