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-rw-r--r--samples/bpf/test_lwt_bpf.c253
1 files changed, 253 insertions, 0 deletions
diff --git a/samples/bpf/test_lwt_bpf.c b/samples/bpf/test_lwt_bpf.c
new file mode 100644
index 0000000..bacc801
--- /dev/null
+++ b/samples/bpf/test_lwt_bpf.c
@@ -0,0 +1,253 @@
+/* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+#include <linux/bpf.h>
+#include <linux/ip.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/icmpv6.h>
+#include <linux/if_ether.h>
+#include "bpf_helpers.h"
+#include <string.h>
+
+# define printk(fmt, ...) \
+ ({ \
+ char ____fmt[] = fmt; \
+ bpf_trace_printk(____fmt, sizeof(____fmt), \
+ ##__VA_ARGS__); \
+ })
+
+#define CB_MAGIC 1234
+
+/* Test: Pass all packets through */
+SEC("nop")
+int do_nop(struct __sk_buff *skb)
+{
+ return BPF_OK;
+}
+
+/* Test: Verify context information can be accessed */
+SEC("test_ctx")
+int do_test_ctx(struct __sk_buff *skb)
+{
+ skb->cb[0] = CB_MAGIC;
+ printk("len %d hash %d protocol %d\n", skb->len, skb->hash,
+ skb->protocol);
+ printk("cb %d ingress_ifindex %d ifindex %d\n", skb->cb[0],
+ skb->ingress_ifindex, skb->ifindex);
+
+ return BPF_OK;
+}
+
+/* Test: Ensure skb->cb[] buffer is cleared */
+SEC("test_cb")
+int do_test_cb(struct __sk_buff *skb)
+{
+ printk("cb0: %x cb1: %x cb2: %x\n", skb->cb[0], skb->cb[1],
+ skb->cb[2]);
+ printk("cb3: %x cb4: %x\n", skb->cb[3], skb->cb[4]);
+
+ return BPF_OK;
+}
+
+/* Test: Verify skb data can be read */
+SEC("test_data")
+int do_test_data(struct __sk_buff *skb)
+{
+ void *data = (void *)(long)skb->data;
+ void *data_end = (void *)(long)skb->data_end;
+ struct iphdr *iph = data;
+
+ if (data + sizeof(*iph) > data_end) {
+ printk("packet truncated\n");
+ return BPF_DROP;
+ }
+
+ printk("src: %x dst: %x\n", iph->saddr, iph->daddr);
+
+ return BPF_OK;
+}
+
+#define IP_CSUM_OFF offsetof(struct iphdr, check)
+#define IP_DST_OFF offsetof(struct iphdr, daddr)
+#define IP_SRC_OFF offsetof(struct iphdr, saddr)
+#define IP_PROTO_OFF offsetof(struct iphdr, protocol)
+#define TCP_CSUM_OFF offsetof(struct tcphdr, check)
+#define UDP_CSUM_OFF offsetof(struct udphdr, check)
+#define IS_PSEUDO 0x10
+
+static inline int rewrite(struct __sk_buff *skb, uint32_t old_ip,
+ uint32_t new_ip, int rw_daddr)
+{
+ int ret, off = 0, flags = IS_PSEUDO;
+ uint8_t proto;
+
+ ret = bpf_skb_load_bytes(skb, IP_PROTO_OFF, &proto, 1);
+ if (ret < 0) {
+ printk("bpf_l4_csum_replace failed: %d\n", ret);
+ return BPF_DROP;
+ }
+
+ switch (proto) {
+ case IPPROTO_TCP:
+ off = TCP_CSUM_OFF;
+ break;
+
+ case IPPROTO_UDP:
+ off = UDP_CSUM_OFF;
+ flags |= BPF_F_MARK_MANGLED_0;
+ break;
+
+ case IPPROTO_ICMPV6:
+ off = offsetof(struct icmp6hdr, icmp6_cksum);
+ break;
+ }
+
+ if (off) {
+ ret = bpf_l4_csum_replace(skb, off, old_ip, new_ip,
+ flags | sizeof(new_ip));
+ if (ret < 0) {
+ printk("bpf_l4_csum_replace failed: %d\n");
+ return BPF_DROP;
+ }
+ }
+
+ ret = bpf_l3_csum_replace(skb, IP_CSUM_OFF, old_ip, new_ip, sizeof(new_ip));
+ if (ret < 0) {
+ printk("bpf_l3_csum_replace failed: %d\n", ret);
+ return BPF_DROP;
+ }
+
+ if (rw_daddr)
+ ret = bpf_skb_store_bytes(skb, IP_DST_OFF, &new_ip, sizeof(new_ip), 0);
+ else
+ ret = bpf_skb_store_bytes(skb, IP_SRC_OFF, &new_ip, sizeof(new_ip), 0);
+
+ if (ret < 0) {
+ printk("bpf_skb_store_bytes() failed: %d\n", ret);
+ return BPF_DROP;
+ }
+
+ return BPF_OK;
+}
+
+/* Test: Verify skb data can be modified */
+SEC("test_rewrite")
+int do_test_rewrite(struct __sk_buff *skb)
+{
+ uint32_t old_ip, new_ip = 0x3fea8c0;
+ int ret;
+
+ ret = bpf_skb_load_bytes(skb, IP_DST_OFF, &old_ip, 4);
+ if (ret < 0) {
+ printk("bpf_skb_load_bytes failed: %d\n", ret);
+ return BPF_DROP;
+ }
+
+ if (old_ip == 0x2fea8c0) {
+ printk("out: rewriting from %x to %x\n", old_ip, new_ip);
+ return rewrite(skb, old_ip, new_ip, 1);
+ }
+
+ return BPF_OK;
+}
+
+static inline int __do_push_ll_and_redirect(struct __sk_buff *skb)
+{
+ uint64_t smac = SRC_MAC, dmac = DST_MAC;
+ int ret, ifindex = DST_IFINDEX;
+ struct ethhdr ehdr;
+
+ ret = bpf_skb_change_head(skb, 14, 0);
+ if (ret < 0) {
+ printk("skb_change_head() failed: %d\n", ret);
+ }
+
+ ehdr.h_proto = __constant_htons(ETH_P_IP);
+ memcpy(&ehdr.h_source, &smac, 6);
+ memcpy(&ehdr.h_dest, &dmac, 6);
+
+ ret = bpf_skb_store_bytes(skb, 0, &ehdr, sizeof(ehdr), 0);
+ if (ret < 0) {
+ printk("skb_store_bytes() failed: %d\n", ret);
+ return BPF_DROP;
+ }
+
+ return bpf_redirect(ifindex, 0);
+}
+
+SEC("push_ll_and_redirect_silent")
+int do_push_ll_and_redirect_silent(struct __sk_buff *skb)
+{
+ return __do_push_ll_and_redirect(skb);
+}
+
+SEC("push_ll_and_redirect")
+int do_push_ll_and_redirect(struct __sk_buff *skb)
+{
+ int ret, ifindex = DST_IFINDEX;
+
+ ret = __do_push_ll_and_redirect(skb);
+ if (ret >= 0)
+ printk("redirected to %d\n", ifindex);
+
+ return ret;
+}
+
+static inline void __fill_garbage(struct __sk_buff *skb)
+{
+ uint64_t f = 0xFFFFFFFFFFFFFFFF;
+
+ bpf_skb_store_bytes(skb, 0, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 8, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 16, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 24, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 32, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 40, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 48, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 56, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 64, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 72, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 80, &f, sizeof(f), 0);
+ bpf_skb_store_bytes(skb, 88, &f, sizeof(f), 0);
+}
+
+SEC("fill_garbage")
+int do_fill_garbage(struct __sk_buff *skb)
+{
+ __fill_garbage(skb);
+ printk("Set initial 96 bytes of header to FF\n");
+ return BPF_OK;
+}
+
+SEC("fill_garbage_and_redirect")
+int do_fill_garbage_and_redirect(struct __sk_buff *skb)
+{
+ int ifindex = DST_IFINDEX;
+ __fill_garbage(skb);
+ printk("redirected to %d\n", ifindex);
+ return bpf_redirect(ifindex, 0);
+}
+
+/* Drop all packets */
+SEC("drop_all")
+int do_drop_all(struct __sk_buff *skb)
+{
+ printk("dropping with: %d\n", BPF_DROP);
+ return BPF_DROP;
+}
+
+char _license[] SEC("license") = "GPL";
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