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vlan_learning.c
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vlan_learning.c
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// Copyright (c) PLUMgrid, Inc.
// Licensed under the Apache License, Version 2.0 (the "License")
#include <bcc/proto.h>
struct ifindex_leaf_t {
int out_ifindex;
int vlan_tci; // populated by phys2virt and used by virt2phys
int vlan_proto; // populated by phys2virt and used by virt2phys
u64 tx_pkts;
u64 tx_bytes;
};
// redirect based on mac -> out_ifindex (auto-learning)
BPF_HASH(egress, int, struct ifindex_leaf_t, 4096);
// redirect based on mac -> out_ifindex (config-driven)
BPF_HASH(ingress, u64, struct ifindex_leaf_t, 4096);
int handle_phys2virt(struct __sk_buff *skb) {
// only handle vlan packets
if (!skb->vlan_present)
return 1;
u8 *cursor = 0;
ethernet: {
struct ethernet_t *ethernet = cursor_advance(cursor, sizeof(*ethernet));
u64 src_mac = ethernet->src;
struct ifindex_leaf_t *leaf = ingress.lookup(&src_mac);
if (leaf) {
lock_xadd(&leaf->tx_pkts, 1);
lock_xadd(&leaf->tx_bytes, skb->len);
// auto-program reverse direction table
int out_ifindex = leaf->out_ifindex;
struct ifindex_leaf_t zleaf = {0};
struct ifindex_leaf_t *out_leaf = egress.lookup_or_try_init(&out_ifindex, &zleaf);
if (out_leaf) {
// to capture potential configuration changes
out_leaf->out_ifindex = skb->ifindex;
out_leaf->vlan_tci = skb->vlan_tci;
out_leaf->vlan_proto = skb->vlan_proto;
}
// pop the vlan header and send to the destination
bpf_skb_vlan_pop(skb);
bpf_clone_redirect(skb, leaf->out_ifindex, 0);
}
}
return 1;
}
int handle_virt2phys(struct __sk_buff *skb) {
u8 *cursor = 0;
ethernet: {
struct ethernet_t *ethernet = cursor_advance(cursor, sizeof(*ethernet));
int src_ifindex = skb->ifindex;
struct ifindex_leaf_t *leaf = egress.lookup(&src_ifindex);
if (leaf) {
lock_xadd(&leaf->tx_pkts, 1);
lock_xadd(&leaf->tx_bytes, skb->len);
bpf_skb_vlan_push(skb, leaf->vlan_proto, leaf->vlan_tci);
bpf_clone_redirect(skb, leaf->out_ifindex, 0);
}
}
return 1;
}