96a8eb1eee
Some of the sample files are causing issues when they are loaded with tc and cls_bpf, meaning tc bails out while trying to parse the resulting ELF file as program/map/etc sections are not present, which can be easily spotted with readelf(1). Currently, BPF samples are including some of the kernel headers and mid term we should change them to refrain from this, really. When dynamic debugging is enabled, we bail out due to undeclared KBUILD_MODNAME, which is easily overlooked in the build as clang spills this along with other noisy warnings from various header includes, and llc still generates an ELF file with mentioned characteristics. For just playing around with BPF examples, this can be a bit of a hurdle to take. Just add a fake KBUILD_MODNAME as a band-aid to fix the issue, same is done in xdp*_kern samples already. Fixes:65d472fb00("samples/bpf: add 'pointer to packet' tests") Fixes:6afb1e28b8("samples/bpf: Add tunnel set/get tests.") Fixes:a3f7461734("cgroup: bpf: Add an example to do cgroup checking in BPF") Reported-by: Chandrasekar Kannan <ckannan@console.to> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
155 lines
3.5 KiB
C
155 lines
3.5 KiB
C
/* Copyright (c) 2016 Facebook
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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 <linux/if_ether.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/in.h>
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#include <linux/tcp.h>
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#include <linux/udp.h>
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#include <uapi/linux/bpf.h>
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#include <net/ip.h>
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#include "bpf_helpers.h"
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#define DEFAULT_PKTGEN_UDP_PORT 9
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#define DEBUG 0
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static int tcp(void *data, uint64_t tp_off, void *data_end)
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{
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struct tcphdr *tcp = data + tp_off;
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if (tcp + 1 > data_end)
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return 0;
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if (tcp->dest == htons(80) || tcp->source == htons(80))
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return TC_ACT_SHOT;
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return 0;
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}
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static int udp(void *data, uint64_t tp_off, void *data_end)
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{
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struct udphdr *udp = data + tp_off;
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if (udp + 1 > data_end)
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return 0;
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if (udp->dest == htons(DEFAULT_PKTGEN_UDP_PORT) ||
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udp->source == htons(DEFAULT_PKTGEN_UDP_PORT)) {
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if (DEBUG) {
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char fmt[] = "udp port 9 indeed\n";
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bpf_trace_printk(fmt, sizeof(fmt));
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}
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return TC_ACT_SHOT;
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}
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return 0;
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}
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static int parse_ipv4(void *data, uint64_t nh_off, void *data_end)
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{
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struct iphdr *iph;
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uint64_t ihl_len;
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iph = data + nh_off;
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if (iph + 1 > data_end)
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return 0;
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if (ip_is_fragment(iph))
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return 0;
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ihl_len = iph->ihl * 4;
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if (iph->protocol == IPPROTO_IPIP) {
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iph = data + nh_off + ihl_len;
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if (iph + 1 > data_end)
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return 0;
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ihl_len += iph->ihl * 4;
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}
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if (iph->protocol == IPPROTO_TCP)
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return tcp(data, nh_off + ihl_len, data_end);
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else if (iph->protocol == IPPROTO_UDP)
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return udp(data, nh_off + ihl_len, data_end);
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return 0;
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}
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static int parse_ipv6(void *data, uint64_t nh_off, void *data_end)
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{
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struct ipv6hdr *ip6h;
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struct iphdr *iph;
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uint64_t ihl_len = sizeof(struct ipv6hdr);
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uint64_t nexthdr;
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ip6h = data + nh_off;
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if (ip6h + 1 > data_end)
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return 0;
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nexthdr = ip6h->nexthdr;
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if (nexthdr == IPPROTO_IPIP) {
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iph = data + nh_off + ihl_len;
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if (iph + 1 > data_end)
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return 0;
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ihl_len += iph->ihl * 4;
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nexthdr = iph->protocol;
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} else if (nexthdr == IPPROTO_IPV6) {
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ip6h = data + nh_off + ihl_len;
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if (ip6h + 1 > data_end)
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return 0;
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ihl_len += sizeof(struct ipv6hdr);
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nexthdr = ip6h->nexthdr;
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}
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if (nexthdr == IPPROTO_TCP)
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return tcp(data, nh_off + ihl_len, data_end);
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else if (nexthdr == IPPROTO_UDP)
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return udp(data, nh_off + ihl_len, data_end);
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return 0;
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}
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struct vlan_hdr {
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uint16_t h_vlan_TCI;
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uint16_t h_vlan_encapsulated_proto;
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};
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SEC("varlen")
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int handle_ingress(struct __sk_buff *skb)
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{
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void *data = (void *)(long)skb->data;
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struct ethhdr *eth = data;
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void *data_end = (void *)(long)skb->data_end;
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uint64_t h_proto, nh_off;
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nh_off = sizeof(*eth);
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if (data + nh_off > data_end)
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return 0;
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h_proto = eth->h_proto;
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if (h_proto == ETH_P_8021Q || h_proto == 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 0;
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h_proto = vhdr->h_vlan_encapsulated_proto;
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}
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if (h_proto == ETH_P_8021Q || h_proto == 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 0;
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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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return parse_ipv4(data, nh_off, data_end);
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else if (h_proto == htons(ETH_P_IPV6))
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return parse_ipv6(data, nh_off, data_end);
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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