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Diffstat (limited to 'Documentation/networking/af_xdp.rst')
| -rw-r--r-- | Documentation/networking/af_xdp.rst | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/Documentation/networking/af_xdp.rst b/Documentation/networking/af_xdp.rst index e14d7d40fc75..eeedc2e826aa 100644 --- a/Documentation/networking/af_xdp.rst +++ b/Documentation/networking/af_xdp.rst @@ -220,7 +220,21 @@ Usage In order to use AF_XDP sockets there are two parts needed. The user-space application and the XDP program. For a complete setup and usage example, please refer to the sample application. The user-space -side is xdpsock_user.c and the XDP side xdpsock_kern.c. +side is xdpsock_user.c and the XDP side is part of libbpf. + +The XDP code sample included in tools/lib/bpf/xsk.c is the following:: + + SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx) + { + int index = ctx->rx_queue_index; + + // A set entry here means that the correspnding queue_id + // has an active AF_XDP socket bound to it. + if (bpf_map_lookup_elem(&xsks_map, &index)) + return bpf_redirect_map(&xsks_map, index, 0); + + return XDP_PASS; + } Naive ring dequeue and enqueue could look like this:: @@ -316,16 +330,16 @@ A: When a netdev of a physical NIC is initialized, Linux usually all the traffic, you can force the netdev to only have 1 queue, queue id 0, and then bind to queue 0. You can use ethtool to do this:: - sudo ethtool -L <interface> combined 1 + sudo ethtool -L <interface> combined 1 If you want to only see part of the traffic, you can program the NIC through ethtool to filter out your traffic to a single queue id that you can bind your XDP socket to. Here is one example in which UDP traffic to and from port 4242 are sent to queue 2:: - sudo ethtool -N <interface> rx-flow-hash udp4 fn - sudo ethtool -N <interface> flow-type udp4 src-port 4242 dst-port \ - 4242 action 2 + sudo ethtool -N <interface> rx-flow-hash udp4 fn + sudo ethtool -N <interface> flow-type udp4 src-port 4242 dst-port \ + 4242 action 2 A number of other ways are possible all up to the capabilitites of the NIC you have. |