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tc_neighbor_sharing.c
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tc_neighbor_sharing.c
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// Copyright (c) PLUMgrid, Inc.
// Licensed under the Apache License, Version 2.0 (the "License")
#include <bcc/proto.h>
struct ipkey {
u32 client_ip;
};
BPF_TABLE("hash", struct ipkey, int, learned_ips, 1024);
// trivial action
int pass(struct __sk_buff *skb) {
return 1;
}
// Process each wan packet, and determine if the packet is in the IP
// table or not. Learned IPs are rate-limited and unclassified are not.
// returns: > 0 when an IP is known
// = 0 when an IP is not known, or non-IP traffic
int classify_wan(struct __sk_buff *skb) {
u8 *cursor = 0;
ethernet: {
struct ethernet_t *ethernet = cursor_advance(cursor, sizeof(*ethernet));
switch (ethernet->type) {
case ETH_P_IP: goto ip;
default: goto EOP;
}
}
ip: {
struct ip_t *ip = cursor_advance(cursor, sizeof(*ip));
u32 dip = ip->dst;
struct ipkey key = {.client_ip=dip};
int *val = learned_ips.lookup(&key);
if (val)
return *val;
goto EOP;
}
EOP:
return 0;
}
// Process each neighbor packet, and store the source IP in the learned table.
// Mark the inserted entry with a non-zero value to be used by the classify_wan
// lookup.
int classify_neighbor(struct __sk_buff *skb) {
u8 *cursor = 0;
ethernet: {
struct ethernet_t *ethernet = cursor_advance(cursor, sizeof(*ethernet));
switch (ethernet->type) {
case ETH_P_IP: goto ip;
default: goto EOP;
}
}
ip: {
struct ip_t *ip = cursor_advance(cursor, sizeof(*ip));
u32 sip = ip->src;
struct ipkey key = {.client_ip=sip};
int val = 1;
learned_ips.update(&key, &val);
goto EOP;
}
EOP:
return 1;
}