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7722517422
This changes the section name for the bpf program embedded in these files to "xdp.frags" to allow the programs to be loaded on drivers that are using an MTU greater than PAGE_SIZE. Rather than directly accessing the buffers, the packet data is now accessed via xdp helper functions to provide an example for those who may need to write more complex programs. v2: remove new unnecessary variable Signed-off-by: Andy Gospodarek <gospo@broadcom.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Lorenzo Bianconi <lorenzo@kernel.org> Link: https://lore.kernel.org/r/20220621175402.35327-1-gospo@broadcom.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
122 lines
2.5 KiB
C
122 lines
2.5 KiB
C
/* Copyright (c) 2016 PLUMgrid
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#define KBUILD_MODNAME "foo"
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#include <uapi/linux/bpf.h>
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#include <linux/in.h>
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#include <linux/if_ether.h>
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#include <linux/if_packet.h>
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#include <linux/if_vlan.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <bpf/bpf_helpers.h>
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struct {
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__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
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__type(key, u32);
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__type(value, long);
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__uint(max_entries, 256);
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} rxcnt SEC(".maps");
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static void swap_src_dst_mac(void *data)
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{
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unsigned short *p = data;
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unsigned short dst[3];
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dst[0] = p[0];
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dst[1] = p[1];
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dst[2] = p[2];
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p[0] = p[3];
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p[1] = p[4];
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p[2] = p[5];
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p[3] = dst[0];
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p[4] = dst[1];
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p[5] = dst[2];
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}
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static int parse_ipv4(void *data, u64 nh_off, void *data_end)
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{
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struct iphdr *iph = data + nh_off;
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if (iph + 1 > data_end)
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return 0;
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return iph->protocol;
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}
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static int parse_ipv6(void *data, u64 nh_off, void *data_end)
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{
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struct ipv6hdr *ip6h = data + nh_off;
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if (ip6h + 1 > data_end)
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return 0;
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return ip6h->nexthdr;
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}
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#define XDPBUFSIZE 64
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SEC("xdp.frags")
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int xdp_prog1(struct xdp_md *ctx)
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{
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__u8 pkt[XDPBUFSIZE] = {};
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void *data_end = &pkt[XDPBUFSIZE-1];
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void *data = pkt;
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struct ethhdr *eth = data;
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int rc = XDP_DROP;
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long *value;
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u16 h_proto;
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u64 nh_off;
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u32 ipproto;
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if (bpf_xdp_load_bytes(ctx, 0, pkt, sizeof(pkt)))
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return rc;
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nh_off = sizeof(*eth);
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if (data + nh_off > data_end)
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return rc;
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h_proto = eth->h_proto;
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/* Handle VLAN tagged packet */
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if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
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struct vlan_hdr *vhdr;
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vhdr = data + nh_off;
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nh_off += sizeof(struct vlan_hdr);
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if (data + nh_off > data_end)
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return rc;
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h_proto = vhdr->h_vlan_encapsulated_proto;
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}
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/* Handle double VLAN tagged packet */
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if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
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struct vlan_hdr *vhdr;
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vhdr = data + nh_off;
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nh_off += sizeof(struct vlan_hdr);
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if (data + nh_off > data_end)
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return rc;
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h_proto = vhdr->h_vlan_encapsulated_proto;
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}
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if (h_proto == htons(ETH_P_IP))
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ipproto = parse_ipv4(data, nh_off, data_end);
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else if (h_proto == htons(ETH_P_IPV6))
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ipproto = parse_ipv6(data, nh_off, data_end);
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else
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ipproto = 0;
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value = bpf_map_lookup_elem(&rxcnt, &ipproto);
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if (value)
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*value += 1;
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if (ipproto == IPPROTO_UDP) {
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swap_src_dst_mac(data);
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rc = XDP_TX;
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}
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return rc;
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}
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char _license[] SEC("license") = "GPL";
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