From: Aaron Yue <haoxu...@andrew.cmu.edu>
From: Aaron Yue <haoxu...@fb.com>
Requires a userspace program to insert ila mappings and mac addresses to
the ila map. Needs a verifier patch to directly allow access to the pkt
from the bpf map.
Signed-off-by: Aaron Yue <haoxu...@fb.com>
Signed-off-by: Aaron Yue <haoxu...@andrew.cmu.edu>
---
samples/bpf/Makefile | 1 +
samples/bpf/ilarouter_xdp.c | 88 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 89 insertions(+)
create mode 100644 samples/bpf/ilarouter_xdp.c
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 15e19bb..827e6e8 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -75,6 +75,7 @@ always += test_cgrp2_tc_kern.o
always += xdp1_kern.o
always += xdp2_kern.o
always += ilarouter_tc.o
+always += ilarouter_xdp.o
HOSTCFLAGS += -I$(objtree)/usr/include
diff --git a/samples/bpf/ilarouter_xdp.c b/samples/bpf/ilarouter_xdp.c
new file mode 100644
index 0000000..24749c4
--- /dev/null
+++ b/samples/bpf/ilarouter_xdp.c
@@ -0,0 +1,88 @@
+/* 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.
+ */
+
+#define MAP_SIZE (1 << 20)
+
+#define KBUILD_MODNAME "ilarouter"
+#include <uapi/linux/if_ether.h>
+#include <uapi/linux/ipv6.h>
+#include <uapi/linux/bpf.h>
+#include "bpf_helpers.h"
+
+struct ila_addr {
+ u64 addr_hi;
+ u64 addr_lo;
+} __packed;
+
+struct ila_info {
+ struct ila_addr addr;
+ u16 mac[3];
+} __packed;
+
+char _license[] SEC("license") = "GPL";
+unsigned int version SEC("version") = 1;
+
+struct bpf_map_def SEC("map_ila_lookup_map") ila_lookup_map = {
+ .type = BPF_MAP_TYPE_HASH,
+ .key_size = sizeof(struct in6_addr),
+ .value_size = sizeof(struct ila_info),
+ .max_entries = MAP_SIZE,
+};
+
+SEC("xdp_ila_lookup")
+int ila_lookup(struct xdp_md *ctx)
+{
+ unsigned long dataptr = (unsigned long)ctx->data;
+ struct ethhdr *eth;
+ struct ipv6hdr *sir;
+ struct ila_addr *pkt_addr;
+ struct ila_info *reply;
+ u16 *dst_mac;
+
+ /* Invalid packet: length too short
+ * compiler optimization/verifier bypass:
+ * this way it won't assume that we copied over a pkt_ptr,
+ * which has register range of 0 (from (r1 + 0))
+ */
+ if (dataptr + sizeof(struct ethhdr) + sizeof(struct ipv6hdr) >
+ (unsigned long)ctx->data_end)
+ return XDP_PASS;
+
+ /* Ethernet header */
+ eth = (struct ethhdr *)dataptr;
+
+ /* Irrelevant packet: not IPv6 */
+ if (eth->h_proto != htons(ETH_P_IPV6))
+ return XDP_PASS;
+
+ /* Sir Address header */
+ sir = (struct ipv6hdr *)(dataptr + sizeof(struct ethhdr));
+
+ /* We don't have to check for C bit or Type, since
+ * userspace mapping inserts guarantees that only valid values
+ * will be inserted into the map in network byte-order.
+ * Hence, a lookup fail implies either C bit/Type is invalid,
+ * or mapping does not exist, in both cases we pass the packet without
+ * modifications.
+ */
+ pkt_addr = (struct ila_addr *)&(sir->daddr);
+ reply = bpf_map_lookup_elem(&ila_lookup_map, pkt_addr);
+
+ if (!reply)
+ return XDP_PASS;
+
+ pkt_addr->addr_hi = reply->addr.addr_hi;
+ pkt_addr->addr_lo = reply->addr.addr_lo;
+
+ dst_mac = (u16 *)eth;
+ dst_mac[0] = reply->mac[0];
+ dst_mac[1] = reply->mac[1];
+ dst_mac[2] = reply->mac[2];
+
+ return XDP_TX;
+}
+
--
2.8.0.rc2
