diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/test_tc_tunnel.c')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_tc_tunnel.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c new file mode 100644 index 000000000000..f541c2de947d --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c @@ -0,0 +1,261 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* In-place tunneling */ + +#include <stdbool.h> +#include <string.h> + +#include <linux/stddef.h> +#include <linux/bpf.h> +#include <linux/if_ether.h> +#include <linux/in.h> +#include <linux/ip.h> +#include <linux/ipv6.h> +#include <linux/tcp.h> +#include <linux/pkt_cls.h> +#include <linux/types.h> + +#include "bpf_endian.h" +#include "bpf_helpers.h" + +static const int cfg_port = 8000; + +struct grev4hdr { + struct iphdr ip; + __be16 flags; + __be16 protocol; +} __attribute__((packed)); + +struct grev6hdr { + struct ipv6hdr ip; + __be16 flags; + __be16 protocol; +} __attribute__((packed)); + +static __always_inline void set_ipv4_csum(struct iphdr *iph) +{ + __u16 *iph16 = (__u16 *)iph; + __u32 csum; + int i; + + iph->check = 0; + +#pragma clang loop unroll(full) + for (i = 0, csum = 0; i < sizeof(*iph) >> 1; i++) + csum += *iph16++; + + iph->check = ~((csum & 0xffff) + (csum >> 16)); +} + +static __always_inline int encap_ipv4(struct __sk_buff *skb, bool with_gre) +{ + struct grev4hdr h_outer; + struct iphdr iph_inner; + struct tcphdr tcph; + __u64 flags; + int olen; + + if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner, + sizeof(iph_inner)) < 0) + return TC_ACT_OK; + + /* 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), + &tcph, sizeof(tcph)) < 0) + return TC_ACT_OK; + + if (tcph.dest != __bpf_constant_htons(cfg_port)) + return TC_ACT_OK; + + flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV4; + if (with_gre) { + flags |= BPF_F_ADJ_ROOM_ENCAP_L4_GRE; + olen = sizeof(h_outer); + } else { + olen = sizeof(h_outer.ip); + } + + /* add room between mac and network header */ + if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags)) + return TC_ACT_SHOT; + + /* prepare new outer network header */ + h_outer.ip = iph_inner; + h_outer.ip.tot_len = bpf_htons(olen + + bpf_htons(h_outer.ip.tot_len)); + if (with_gre) { + h_outer.ip.protocol = IPPROTO_GRE; + h_outer.protocol = bpf_htons(ETH_P_IP); + h_outer.flags = 0; + } else { + h_outer.ip.protocol = IPPROTO_IPIP; + } + + set_ipv4_csum((void *)&h_outer.ip); + + /* store new outer network header */ + if (bpf_skb_store_bytes(skb, ETH_HLEN, &h_outer, olen, + BPF_F_INVALIDATE_HASH) < 0) + return TC_ACT_SHOT; + + return TC_ACT_OK; +} + +static __always_inline int encap_ipv6(struct __sk_buff *skb, bool with_gre) +{ + struct ipv6hdr iph_inner; + struct grev6hdr h_outer; + struct tcphdr tcph; + __u64 flags; + int olen; + + if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner, + sizeof(iph_inner)) < 0) + return TC_ACT_OK; + + /* filter only packets we want */ + if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(iph_inner), + &tcph, sizeof(tcph)) < 0) + return TC_ACT_OK; + + if (tcph.dest != __bpf_constant_htons(cfg_port)) + return TC_ACT_OK; + + flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV6; + if (with_gre) { + flags |= BPF_F_ADJ_ROOM_ENCAP_L4_GRE; + olen = sizeof(h_outer); + } else { + olen = sizeof(h_outer.ip); + } + + + /* add room between mac and network header */ + if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags)) + return TC_ACT_SHOT; + + /* prepare new outer network header */ + h_outer.ip = iph_inner; + h_outer.ip.payload_len = bpf_htons(olen + + bpf_ntohs(h_outer.ip.payload_len)); + if (with_gre) { + h_outer.ip.nexthdr = IPPROTO_GRE; + h_outer.protocol = bpf_htons(ETH_P_IPV6); + h_outer.flags = 0; + } else { + h_outer.ip.nexthdr = IPPROTO_IPV6; + } + + /* store new outer network header */ + if (bpf_skb_store_bytes(skb, ETH_HLEN, &h_outer, olen, + BPF_F_INVALIDATE_HASH) < 0) + return TC_ACT_SHOT; + + return TC_ACT_OK; +} + +SEC("encap_ipip") +int __encap_ipip(struct __sk_buff *skb) +{ + if (skb->protocol == __bpf_constant_htons(ETH_P_IP)) + return encap_ipv4(skb, false); + else + return TC_ACT_OK; +} + +SEC("encap_gre") +int __encap_gre(struct __sk_buff *skb) +{ + if (skb->protocol == __bpf_constant_htons(ETH_P_IP)) + return encap_ipv4(skb, true); + else + return TC_ACT_OK; +} + +SEC("encap_ip6tnl") +int __encap_ip6tnl(struct __sk_buff *skb) +{ + if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6)) + return encap_ipv6(skb, false); + else + return TC_ACT_OK; +} + +SEC("encap_ip6gre") +int __encap_ip6gre(struct __sk_buff *skb) +{ + if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6)) + return encap_ipv6(skb, true); + else + return TC_ACT_OK; +} + +static int decap_internal(struct __sk_buff *skb, int off, int len, char proto) +{ + char buf[sizeof(struct grev6hdr)]; + int olen; + + switch (proto) { + case IPPROTO_IPIP: + case IPPROTO_IPV6: + olen = len; + break; + case IPPROTO_GRE: + olen = len + 4 /* gre hdr */; + break; + default: + return TC_ACT_OK; + } + + if (bpf_skb_adjust_room(skb, -olen, BPF_ADJ_ROOM_MAC, + BPF_F_ADJ_ROOM_FIXED_GSO)) + return TC_ACT_SHOT; + + return TC_ACT_OK; +} + +static int decap_ipv4(struct __sk_buff *skb) +{ + struct iphdr iph_outer; + + if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer, + sizeof(iph_outer)) < 0) + return TC_ACT_OK; + + if (iph_outer.ihl != 5) + return TC_ACT_OK; + + return decap_internal(skb, ETH_HLEN, sizeof(iph_outer), + iph_outer.protocol); +} + +static int decap_ipv6(struct __sk_buff *skb) +{ + struct ipv6hdr iph_outer; + + if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer, + sizeof(iph_outer)) < 0) + return TC_ACT_OK; + + return decap_internal(skb, ETH_HLEN, sizeof(iph_outer), + iph_outer.nexthdr); +} + +SEC("decap") +int decap_f(struct __sk_buff *skb) +{ + switch (skb->protocol) { + case __bpf_constant_htons(ETH_P_IP): + return decap_ipv4(skb); + case __bpf_constant_htons(ETH_P_IPV6): + return decap_ipv6(skb); + default: + /* does not match, ignore */ + return TC_ACT_OK; + } +} + +char __license[] SEC("license") = "GPL"; |