diff options
author | Hangbin Liu <liuhangbin@gmail.com> | 2021-01-22 10:50:07 +0800 |
---|---|---|
committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-01-23 00:24:37 +0100 |
commit | 6e66fbb10597f31e88c575e07640978f376abcd3 (patch) | |
tree | 1a62ae101f86d93044f852505922be2698d7a406 /samples/bpf/xdp_redirect_map_kern.c | |
parent | bpf: Fix typo in scalar{,32}_min_max_rsh comments (diff) | |
download | linux-dev-6e66fbb10597f31e88c575e07640978f376abcd3.tar.xz linux-dev-6e66fbb10597f31e88c575e07640978f376abcd3.zip |
samples/bpf: Add xdp program on egress for xdp_redirect_map
This patch add a xdp program on egress to show that we can modify
the packet on egress. In this sample we will set the pkt's src
mac to egress's mac address. The xdp_prog will be attached when
-X option supplied.
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/20210122025007.2968381-1-liuhangbin@gmail.com
Diffstat (limited to 'samples/bpf/xdp_redirect_map_kern.c')
-rw-r--r-- | samples/bpf/xdp_redirect_map_kern.c | 60 |
1 files changed, 55 insertions, 5 deletions
diff --git a/samples/bpf/xdp_redirect_map_kern.c b/samples/bpf/xdp_redirect_map_kern.c index 6489352ab7a4..a92b8e567bdd 100644 --- a/samples/bpf/xdp_redirect_map_kern.c +++ b/samples/bpf/xdp_redirect_map_kern.c @@ -19,12 +19,22 @@ #include <linux/ipv6.h> #include <bpf/bpf_helpers.h> +/* The 2nd xdp prog on egress does not support skb mode, so we define two + * maps, tx_port_general and tx_port_native. + */ struct { __uint(type, BPF_MAP_TYPE_DEVMAP); __uint(key_size, sizeof(int)); __uint(value_size, sizeof(int)); __uint(max_entries, 100); -} tx_port SEC(".maps"); +} tx_port_general SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_DEVMAP); + __uint(key_size, sizeof(int)); + __uint(value_size, sizeof(struct bpf_devmap_val)); + __uint(max_entries, 100); +} tx_port_native SEC(".maps"); /* Count RX packets, as XDP bpf_prog doesn't get direct TX-success * feedback. Redirect TX errors can be caught via a tracepoint. @@ -36,6 +46,14 @@ struct { __uint(max_entries, 1); } rxcnt SEC(".maps"); +/* map to store egress interface mac address */ +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, u32); + __type(value, __be64); + __uint(max_entries, 1); +} tx_mac SEC(".maps"); + static void swap_src_dst_mac(void *data) { unsigned short *p = data; @@ -52,17 +70,16 @@ static void swap_src_dst_mac(void *data) p[5] = dst[2]; } -SEC("xdp_redirect_map") -int xdp_redirect_map_prog(struct xdp_md *ctx) +static __always_inline int xdp_redirect_map(struct xdp_md *ctx, void *redirect_map) { void *data_end = (void *)(long)ctx->data_end; void *data = (void *)(long)ctx->data; struct ethhdr *eth = data; int rc = XDP_DROP; - int vport, port = 0, m = 0; long *value; u32 key = 0; u64 nh_off; + int vport; nh_off = sizeof(*eth); if (data + nh_off > data_end) @@ -79,7 +96,40 @@ int xdp_redirect_map_prog(struct xdp_md *ctx) swap_src_dst_mac(data); /* send packet out physical port */ - return bpf_redirect_map(&tx_port, vport, 0); + return bpf_redirect_map(redirect_map, vport, 0); +} + +SEC("xdp_redirect_general") +int xdp_redirect_map_general(struct xdp_md *ctx) +{ + return xdp_redirect_map(ctx, &tx_port_general); +} + +SEC("xdp_redirect_native") +int xdp_redirect_map_native(struct xdp_md *ctx) +{ + return xdp_redirect_map(ctx, &tx_port_native); +} + +SEC("xdp_devmap/map_prog") +int xdp_redirect_map_egress(struct xdp_md *ctx) +{ + void *data_end = (void *)(long)ctx->data_end; + void *data = (void *)(long)ctx->data; + struct ethhdr *eth = data; + __be64 *mac; + u32 key = 0; + u64 nh_off; + + nh_off = sizeof(*eth); + if (data + nh_off > data_end) + return XDP_DROP; + + mac = bpf_map_lookup_elem(&tx_mac, &key); + if (mac) + __builtin_memcpy(eth->h_source, mac, ETH_ALEN); + + return XDP_PASS; } /* Redirect require an XDP bpf_prog loaded on the TX device */ |