Files
XDP-Firewall/src/xdp/prog.c
Christian Deacon fd013b4b4a Clean up code.
2025-03-24 10:52:41 -04:00

671 lines
17 KiB
C

#include <linux/if_ether.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/udp.h>
#include <linux/tcp.h>
#include <linux/icmp.h>
#include <linux/icmpv6.h>
#include <linux/in.h>
#include <stdatomic.h>
#include <common/all.h>
#include <xdp/utils/rl.h>
#include <xdp/utils/logging.h>
#include <xdp/utils/stats.h>
#include <xdp/utils/helpers.h>
#include <xdp/utils/maps.h>
struct
{
__uint(priority, 10);
__uint(XDP_PASS, 1);
} XDP_RUN_CONFIG(xdp_prog_main);
SEC("xdp_prog")
int xdp_prog_main(struct xdp_md *ctx)
{
// Initialize data.
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
// Retrieve stats map value.
u32 key = 0;
stats_t* stats = bpf_map_lookup_elem(&map_stats, &key);
// Scan ethernet header.
struct ethhdr *eth = data;
// Check if the ethernet header is valid.
if (unlikely(eth + 1 > (struct ethhdr *)data_end))
{
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
return XDP_DROP;
}
// Check Ethernet protocol.
if (unlikely(eth->h_proto != htons(ETH_P_IP) && eth->h_proto != htons(ETH_P_IPV6)))
{
inc_pkt_stats(stats, STATS_TYPE_PASSED);
return XDP_PASS;
}
// Initialize IP headers.
struct iphdr *iph = NULL;
struct ipv6hdr *iph6 = NULL;
u128 src_ip6 = 0;
// Set IPv4 and IPv6 common variables.
if (eth->h_proto == htons(ETH_P_IPV6))
{
iph6 = data + sizeof(struct ethhdr);
if (unlikely(iph6 + 1 > (struct ipv6hdr *)data_end))
{
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
return XDP_DROP;
}
memcpy(&src_ip6, iph6->saddr.in6_u.u6_addr32, sizeof(src_ip6));
}
else
{
iph = data + sizeof(struct ethhdr);
if (unlikely(iph + 1 > (struct iphdr *)data_end))
{
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
return XDP_DROP;
}
}
// We only want to process TCP, UDP, and ICMP packets.
if ((iph6 && iph6->nexthdr != IPPROTO_UDP && iph6->nexthdr != IPPROTO_TCP && iph6->nexthdr != IPPROTO_ICMP) && (iph && iph->protocol != IPPROTO_UDP && iph->protocol != IPPROTO_TCP && iph->protocol != IPPROTO_ICMP))
{
inc_pkt_stats(stats, STATS_TYPE_PASSED);
return XDP_PASS;
}
// Retrieve nanoseconds since system boot as timestamp.
u64 now = bpf_ktime_get_ns();
// Check block map.
u64 *blocked = NULL;
if (iph6)
{
blocked = bpf_map_lookup_elem(&map_block6, &src_ip6);
}
else if (iph)
{
blocked = bpf_map_lookup_elem(&map_block, &iph->saddr);
}
if (blocked != NULL)
{
if (*blocked > 0 && now > *blocked)
{
// Remove element from map.
if (iph6)
{
bpf_map_delete_elem(&map_block6, &src_ip6);
}
else if (iph)
{
bpf_map_delete_elem(&map_block, &iph->saddr);
}
}
else
{
#ifdef DO_STATS_ON_BLOCK_MAP
// Increase blocked stats entry.
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
#endif
// They're still blocked. Drop the packet.
return XDP_DROP;
}
}
#ifdef ENABLE_IP_RANGE_DROP
if (iph && check_ip_range_drop(iph->saddr))
{
#ifdef DO_STATS_ON_IP_RANGE_DROP_MAP
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
#endif
return XDP_DROP;
}
#endif
#ifdef ENABLE_FILTERS
// Retrieve total packet length.
u16 pkt_len = data_end - data;
// Parse layer-4 headers and determine source port and protocol.
struct tcphdr *tcph = NULL;
struct udphdr *udph = NULL;
struct icmphdr *icmph = NULL;
struct icmp6hdr *icmp6h = NULL;
u16 src_port = 0;
#ifdef ENABLE_FILTER_LOGGING
u16 dst_port = 0;
#endif
u8 protocol = 0;
if (iph6)
{
protocol = iph6->nexthdr;
switch (iph6->nexthdr)
{
case IPPROTO_TCP:
// Scan TCP header.
tcph = data + sizeof(struct ethhdr) + sizeof(struct ipv6hdr);
// Check TCP header.
if (unlikely(tcph + 1 > (struct tcphdr *)data_end))
{
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
return XDP_DROP;
}
src_port = tcph->source;
#ifdef ENABLE_FILTER_LOGGING
dst_port = tcph->dest;
#endif
break;
case IPPROTO_UDP:
// Scan UDP header.
udph = data + sizeof(struct ethhdr) + sizeof(struct ipv6hdr);
// Check TCP header.
if (unlikely(udph + 1 > (struct udphdr *)data_end))
{
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
return XDP_DROP;
}
src_port = udph->source;
#ifdef ENABLE_FILTER_LOGGING
dst_port = udph->dest;
#endif
break;
case IPPROTO_ICMPV6:
// Scan ICMPv6 header.
icmp6h = data + sizeof(struct ethhdr) + sizeof(struct ipv6hdr);
// Check ICMPv6 header.
if (unlikely(icmp6h + 1 > (struct icmp6hdr *)data_end))
{
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
return XDP_DROP;
}
break;
}
}
else if (iph)
{
protocol = iph->protocol;
switch (iph->protocol)
{
case IPPROTO_TCP:
// Scan TCP header.
tcph = data + sizeof(struct ethhdr) + (iph->ihl * 4);
// Check TCP header.
if (unlikely(tcph + 1 > (struct tcphdr *)data_end))
{
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
return XDP_DROP;
}
src_port = tcph->source;
#ifdef ENABLE_FILTER_LOGGING
dst_port = tcph->dest;
#endif
break;
case IPPROTO_UDP:
// Scan UDP header.
udph = data + sizeof(struct ethhdr) + (iph->ihl * 4);
// Check UDP header.
if (unlikely(udph + 1 > (struct udphdr *)data_end))
{
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
return XDP_DROP;
}
src_port = udph->source;
#ifdef ENABLE_FILTER_LOGGING
dst_port = udph->dest;
#endif
break;
case IPPROTO_ICMP:
// Scan ICMP header.
icmph = data + sizeof(struct ethhdr) + (iph->ihl * 4);
// Check ICMP header.
if (unlikely(icmph + 1 > (struct icmphdr *)data_end))
{
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
return XDP_DROP;
}
break;
}
}
#ifdef ENABLE_FILTERS
// Update client stats (PPS/BPS).
u64 ip_pps = 0;
u64 ip_bps = 0;
u64 flow_pps = 0;
u64 flow_bps = 0;
#if defined(ENABLE_RL_IP) || defined(ENABLE_RL_FLOW)
if (iph)
{
#ifdef ENABLE_RL_IP
update_ip_stats(&ip_pps, &ip_bps, iph->saddr, pkt_len, now);
#endif
#ifdef ENABLE_RL_FLOW
update_flow_stats(&flow_pps, &flow_bps, iph->saddr, src_port, protocol, pkt_len, now);
#endif
}
else if (iph6)
{
#ifdef ENABLE_RL_IP
update_ip6_stats(&ip_pps, &ip_bps, &src_ip6, pkt_len, now);
#endif
#ifdef ENABLE_RL_FLOW
update_flow6_stats(&flow_pps, &flow_bps, &src_ip6, src_port, protocol, pkt_len, now);
#endif
}
#endif
#endif
int action = 0;
u64 block_time = 1;
#pragma unroll 30
for (int i = 0; i < MAX_FILTERS; i++)
{
u32 key = i;
filter_t *filter = bpf_map_lookup_elem(&map_filters, &key);
if (!filter || !filter->set)
{
break;
}
#ifdef ENABLE_RL_IP
// Check source IP rate limits.
if (filter->do_ip_pps && ip_pps < filter->ip_pps)
{
continue;
}
if (filter->do_ip_bps && ip_bps < filter->ip_bps)
{
continue;
}
#endif
#ifdef ENABLE_RL_FLOW
// Check source flow rate limits.
if (filter->do_flow_pps && flow_pps < filter->flow_pps)
{
continue;
}
if (filter->do_flow_bps && flow_bps < filter->flow_bps)
{
continue;
}
#endif
// Do specific IPv6.
if (iph6)
{
// Source address.
if (filter->ip.src_ip6[0] != 0 && (iph6->saddr.in6_u.u6_addr32[0] != filter->ip.src_ip6[0] || iph6->saddr.in6_u.u6_addr32[1] != filter->ip.src_ip6[1] || iph6->saddr.in6_u.u6_addr32[2] != filter->ip.src_ip6[2] || iph6->saddr.in6_u.u6_addr32[3] != filter->ip.src_ip6[3]))
{
continue;
}
// Destination address.
if (filter->ip.dst_ip6[0] != 0 && (iph6->daddr.in6_u.u6_addr32[0] != filter->ip.dst_ip6[0] || iph6->daddr.in6_u.u6_addr32[1] != filter->ip.dst_ip6[1] || iph6->daddr.in6_u.u6_addr32[2] != filter->ip.dst_ip6[2] || iph6->daddr.in6_u.u6_addr32[3] != filter->ip.dst_ip6[3]))
{
continue;
}
#ifdef ALLOW_SINGLE_IP_V4_V6
if (filter->ip.src_ip != 0 || filter->ip.dst_ip != 0)
{
continue;
}
#endif
// Max TTL length.
if (filter->ip.do_max_ttl && filter->ip.max_ttl < iph6->hop_limit)
{
continue;
}
// Min TTL length.
if (filter->ip.do_min_ttl && filter->ip.min_ttl > iph6->hop_limit)
{
continue;
}
// Max packet length.
if (filter->ip.do_max_len && filter->ip.max_len < pkt_len)
{
continue;
}
// Min packet length.
if (filter->ip.do_min_len && filter->ip.min_len > pkt_len)
{
continue;
}
}
else if (iph)
{
// Source address.
if (filter->ip.src_ip)
{
if (filter->ip.src_cidr == 32 && iph->saddr != filter->ip.src_ip)
{
continue;
}
if (!is_ip_in_range(iph->saddr, filter->ip.src_ip, filter->ip.src_cidr))
{
continue;
}
}
// Destination address.
if (filter->ip.dst_ip)
{
if (filter->ip.dst_cidr == 32 && iph->daddr != filter->ip.dst_ip)
{
continue;
}
if (!is_ip_in_range(iph->daddr, filter->ip.dst_ip, filter->ip.dst_cidr))
{
continue;
}
}
#ifdef ALLOW_SINGLE_IP_V4_V6
if ((filter->ip.src_ip6[0] != 0 || filter->ip.src_ip6[1] != 0 || filter->ip.src_ip6[2] != 0 || filter->ip.src_ip6[3] != 0) || (filter->ip.dst_ip6[0] != 0 || filter->ip.dst_ip6[1] != 0 || filter->ip.dst_ip6[2] != 0 || filter->ip.dst_ip6[3] != 0))
{
continue;
}
#endif
// TOS.
if (filter->ip.do_tos && filter->ip.tos != iph->tos)
{
continue;
}
// Max TTL.
if (filter->ip.do_max_ttl && filter->ip.max_ttl < iph->ttl)
{
continue;
}
// Min TTL.
if (filter->ip.do_min_ttl && filter->ip.min_ttl > iph->ttl)
{
continue;
}
// Max packet length.
if (filter->ip.do_max_len && filter->ip.max_len < pkt_len)
{
continue;
}
// Min packet length.
if (filter->ip.do_min_len && filter->ip.min_len > pkt_len)
{
continue;
}
}
// Do TCP options.
if (filter->tcp.enabled)
{
if (!tcph)
{
continue;
}
// Source port checks.
if (filter->tcp.do_sport_min && tcph->source < filter->tcp.sport_min)
{
continue;
}
if (filter->tcp.do_sport_max && tcph->source > filter->tcp.sport_max)
{
continue;
}
// Destination port checks.
if (filter->tcp.do_dport_min && tcph->dest < filter->tcp.dport_min)
{
continue;
}
if (filter->tcp.do_dport_max && tcph->dest > filter->tcp.dport_max)
{
continue;
}
// URG flag.
if (filter->tcp.do_urg && filter->tcp.urg != tcph->urg)
{
continue;
}
// ACK flag.
if (filter->tcp.do_ack && filter->tcp.ack != tcph->ack)
{
continue;
}
// RST flag.
if (filter->tcp.do_rst && filter->tcp.rst != tcph->rst)
{
continue;
}
// PSH flag.
if (filter->tcp.do_psh && filter->tcp.psh != tcph->psh)
{
continue;
}
// SYN flag.
if (filter->tcp.do_syn && filter->tcp.syn != tcph->syn)
{
continue;
}
// FIN flag.
if (filter->tcp.do_fin && filter->tcp.fin != tcph->fin)
{
continue;
}
// ECE flag.
if (filter->tcp.do_ece && filter->tcp.ece != tcph->ece)
{
continue;
}
// CWR flag.
if (filter->tcp.do_cwr && filter->tcp.cwr != tcph->cwr)
{
continue;
}
}
else if (filter->udp.enabled)
{
if (!udph)
{
continue;
}
// Source port checks.
if (filter->udp.do_sport_min && udph->source < filter->udp.sport_min)
{
continue;
}
if (filter->udp.do_sport_max && udph->source > filter->udp.sport_max)
{
continue;
}
// Destination port checks.
if (filter->udp.do_dport_min && udph->dest < filter->udp.dport_min)
{
continue;
}
if (filter->udp.do_dport_max && udph->dest > filter->udp.dport_max)
{
continue;
}
}
else if (filter->icmp.enabled)
{
if (icmph)
{
// Code.
if (filter->icmp.do_code && filter->icmp.code != icmph->code)
{
continue;
}
// Type.
if (filter->icmp.do_type && filter->icmp.type != icmph->type)
{
continue;
}
}
else if (icmp6h)
{
// Code.
if (filter->icmp.do_code && filter->icmp.code != icmp6h->icmp6_code)
{
continue;
}
// Type.
if (filter->icmp.do_type && filter->icmp.type != icmp6h->icmp6_type)
{
continue;
}
}
else
{
continue;
}
}
#ifdef ENABLE_FILTER_LOGGING
if (filter->log > 0)
{
log_filter_msg(iph, iph6, src_port, dst_port, protocol, now, ip_pps, ip_bps, flow_pps, flow_bps, pkt_len, i);
}
#endif
// Matched.
action = filter->action;
block_time = filter->block_time;
goto matched;
}
#endif
inc_pkt_stats(stats, STATS_TYPE_PASSED);
return XDP_PASS;
#ifdef ENABLE_FILTERS
matched:
if (action == 0)
{
// Before dropping, update the block map.
if (block_time > 0)
{
u64 new_time = now + (block_time * NANO_TO_SEC);
if (iph6)
{
bpf_map_update_elem(&map_block6, &src_ip6, &new_time, BPF_ANY);
}
else if (iph)
{
bpf_map_update_elem(&map_block, &iph->saddr, &new_time, BPF_ANY);
}
}
inc_pkt_stats(stats, STATS_TYPE_DROPPED);
return XDP_DROP;
}
else
{
inc_pkt_stats(stats, STATS_TYPE_ALLOWED);
}
return XDP_PASS;
#endif
}
char _license[] SEC("license") = "GPL";
__uint(xsk_prog_version, XDP_DISPATCHER_VERSION) SEC(XDP_METADATA_SECTION);