samples/bpf: add 'pointer to packet' tests

[cascardo/linux.git] / samples / bpf / parse_varlen.c

diff --git a/samples/bpf/parse_varlen.c b/samples/bpf/parse_varlen.c
new file mode 100644 (file)
index 0000000..edab34d
--- /dev/null
+++ b/samples/bpf/parse_varlen.c
@@ -0,0 +1,153 @@
+/* Copyright (c) 2016 Facebook
+ *
+ * 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.
+ */
+#include <linux/if_ether.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/in.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <uapi/linux/bpf.h>
+#include <net/ip.h>
+#include "bpf_helpers.h"
+
+#define DEFAULT_PKTGEN_UDP_PORT 9
+#define DEBUG 0
+
+static int tcp(void *data, uint64_t tp_off, void *data_end)
+{
+       struct tcphdr *tcp = data + tp_off;
+
+       if (tcp + 1 > data_end)
+               return 0;
+       if (tcp->dest == htons(80) || tcp->source == htons(80))
+               return TC_ACT_SHOT;
+       return 0;
+}
+
+static int udp(void *data, uint64_t tp_off, void *data_end)
+{
+       struct udphdr *udp = data + tp_off;
+
+       if (udp + 1 > data_end)
+               return 0;
+       if (udp->dest == htons(DEFAULT_PKTGEN_UDP_PORT) ||
+           udp->source == htons(DEFAULT_PKTGEN_UDP_PORT)) {
+               if (DEBUG) {
+                       char fmt[] = "udp port 9 indeed\n";
+
+                       bpf_trace_printk(fmt, sizeof(fmt));
+               }
+               return TC_ACT_SHOT;
+       }
+       return 0;
+}
+
+static int parse_ipv4(void *data, uint64_t nh_off, void *data_end)
+{
+       struct iphdr *iph;
+       uint64_t ihl_len;
+
+       iph = data + nh_off;
+       if (iph + 1 > data_end)
+               return 0;
+
+       if (ip_is_fragment(iph))
+               return 0;
+       ihl_len = iph->ihl * 4;
+
+       if (iph->protocol == IPPROTO_IPIP) {
+               iph = data + nh_off + ihl_len;
+               if (iph + 1 > data_end)
+                       return 0;
+               ihl_len += iph->ihl * 4;
+       }
+
+       if (iph->protocol == IPPROTO_TCP)
+               return tcp(data, nh_off + ihl_len, data_end);
+       else if (iph->protocol == IPPROTO_UDP)
+               return udp(data, nh_off + ihl_len, data_end);
+       return 0;
+}
+
+static int parse_ipv6(void *data, uint64_t nh_off, void *data_end)
+{
+       struct ipv6hdr *ip6h;
+       struct iphdr *iph;
+       uint64_t ihl_len = sizeof(struct ipv6hdr);
+       uint64_t nexthdr;
+
+       ip6h = data + nh_off;
+       if (ip6h + 1 > data_end)
+               return 0;
+
+       nexthdr = ip6h->nexthdr;
+
+       if (nexthdr == IPPROTO_IPIP) {
+               iph = data + nh_off + ihl_len;
+               if (iph + 1 > data_end)
+                       return 0;
+               ihl_len += iph->ihl * 4;
+               nexthdr = iph->protocol;
+       } else if (nexthdr == IPPROTO_IPV6) {
+               ip6h = data + nh_off + ihl_len;
+               if (ip6h + 1 > data_end)
+                       return 0;
+               ihl_len += sizeof(struct ipv6hdr);
+               nexthdr = ip6h->nexthdr;
+       }
+
+       if (nexthdr == IPPROTO_TCP)
+               return tcp(data, nh_off + ihl_len, data_end);
+       else if (nexthdr == IPPROTO_UDP)
+               return udp(data, nh_off + ihl_len, data_end);
+       return 0;
+}
+
+struct vlan_hdr {
+       uint16_t h_vlan_TCI;
+       uint16_t h_vlan_encapsulated_proto;
+};
+
+SEC("varlen")
+int handle_ingress(struct __sk_buff *skb)
+{
+       void *data = (void *)(long)skb->data;
+       struct ethhdr *eth = data;
+       void *data_end = (void *)(long)skb->data_end;
+       uint64_t h_proto, nh_off;
+
+       nh_off = sizeof(*eth);
+       if (data + nh_off > data_end)
+               return 0;
+
+       h_proto = eth->h_proto;
+
+       if (h_proto == ETH_P_8021Q || h_proto == ETH_P_8021AD) {
+               struct vlan_hdr *vhdr;
+
+               vhdr = data + nh_off;
+               nh_off += sizeof(struct vlan_hdr);
+               if (data + nh_off > data_end)
+                       return 0;
+               h_proto = vhdr->h_vlan_encapsulated_proto;
+       }
+       if (h_proto == ETH_P_8021Q || h_proto == ETH_P_8021AD) {
+               struct vlan_hdr *vhdr;
+
+               vhdr = data + nh_off;
+               nh_off += sizeof(struct vlan_hdr);
+               if (data + nh_off > data_end)
+                       return 0;
+               h_proto = vhdr->h_vlan_encapsulated_proto;
+       }
+       if (h_proto == htons(ETH_P_IP))
+               return parse_ipv4(data, nh_off, data_end);
+       else if (h_proto == htons(ETH_P_IPV6))
+               return parse_ipv6(data, nh_off, data_end);
+       return 0;
+}
+char _license[] SEC("license") = "GPL";