On Wed, 1 Nov 2017 13:18:04 +0530 Christina Jacob
<christina.jacob.koik...@gmail.com> wrote:
> From: Christina Jacob <christina.ja...@cavium.com>
>
> Implements port to port forwarding with route table and arp table
> lookup for ipv4 packets using bpf_redirect helper function and
> lpm_trie map.
> Signed-off-by: Christina Jacob <christina.ja...@cavium.com>
There is usually a line between the desc and Signed-off-by.
> ---
> samples/bpf/Makefile | 4 +
> samples/bpf/xdp_router_ipv4_kern.c | 181 ++++++++++
> samples/bpf/xdp_router_ipv4_user.c | 657
> +++++++++++++++++++++++++++++++++++++
> 3 files changed, 842 insertions(+)
>
[...]
> diff --git a/samples/bpf/xdp_router_ipv4_kern.c
> b/samples/bpf/xdp_router_ipv4_kern.c
> new file mode 100644
> index 0000000..70a5907
> --- /dev/null
> +++ b/samples/bpf/xdp_router_ipv4_kern.c
> @@ -0,0 +1,181 @@
> +/* Copyright (C) 2017 Cavium, Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of version 2 of the GNU General Public License
> + * as published by the Free Software Foundation.
> + */
[...]
> +SEC("xdp3")
> +int xdp_prog3(struct xdp_md *ctx)
You changed the filename from xdp3 to xdp_router_ipv4, but you didn't
change the name in he code.
> +{
> + void *data_end = (void *)(long)ctx->data_end;
> + __be64 *dest_mac = NULL, *src_mac = NULL;
> + void *data = (void *)(long)ctx->data;
> + struct trie_value *prefix_value;
> + int rc = XDP_DROP, forward_to;
> + struct ethhdr *eth = data;
> + union key_4 key4;
> + long *value;
> + u16 h_proto;
> + u32 ipproto;
> + u64 nh_off;
> +
[..]
> + if (h_proto == htons(ETH_P_ARP)) {
> + return XDP_PASS;
> + } else if (h_proto == htons(ETH_P_IP)) {
> + struct direct_map *direct_entry;
> + __be32 src_ip = 0, dest_ip = 0;
> +
> + ipproto = parse_ipv4(data, nh_off, data_end, &src_ip, &dest_ip);
> + direct_entry = (struct direct_map *)bpf_map_lookup_elem
> + (&exact_match, &dest_ip);
I don't think you need this type-casting.
> + /* Check for exact match, this would give a faster lookup*/
> + if (direct_entry && direct_entry->mac && direct_entry->arp.mac)
> {
> + src_mac = &direct_entry->mac;
> + dest_mac = &direct_entry->arp.mac;
> + forward_to = direct_entry->ifindex;
> + } else {
> + /* Look up in the trie for lpm*/
> + key4.b32[0] = 32;
> + key4.b8[4] = dest_ip & 0xff;
> + key4.b8[5] = (dest_ip >> 8) & 0xff;
> + key4.b8[6] = (dest_ip >> 16) & 0xff;
> + key4.b8[7] = (dest_ip >> 24) & 0xff;
> + prefix_value = ((struct trie_value *)bpf_map_lookup_elem
> + (&lpm_map, &key4));
> + if (!prefix_value)
> + return XDP_DROP;
> + src_mac = &prefix_value->value;
> + if (!src_mac)
> + return XDP_DROP;
> + dest_mac = (__be64 *)bpf_map_lookup_elem(&arp_table,
> &dest_ip);
> + if (!dest_mac) {
> + if (!prefix_value->gw)
> + return XDP_DROP;
> + dest_ip = *(__be32 *)&prefix_value->gw;
> + dest_mac = (__be64
> *)bpf_map_lookup_elem(&arp_table, &dest_ip);
> + }
> + forward_to = prefix_value->ifindex;
> + }
> + } else {
> + ipproto = 0;
> + }
> + if (src_mac && dest_mac) {
> + set_src_dst_mac(data, src_mac, dest_mac);
> + value = bpf_map_lookup_elem(&rxcnt, &ipproto);
> + if (value)
> + *value += 1;
> + return bpf_redirect(forward_to, 0);
Notice that using bpf_redirect() is slow, while using bpf_redirect_map()
is fast. Using bpf_redirect_map() requires a little more book keeping,
but the performance gain is worth it.
Raw benchmarks on my system show:
* bpf_redirect() max at 7Mpps
* bpf_redirect_map() at 13Mpps
Trying out your program on my systems showed it jumps between 5.6Mpps
to 7Mpps. And it seems to be correlated with matching direct_entry.
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
