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Added blocktime filter option and optimized code.

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This commit is contained in:
Christian Deacon
2020-05-07 13:18:43 +00:00
parent f8730a511c
commit d17f5a4f54
5 changed files with 385 additions and 328 deletions
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19
README.md
View File

@@ -22,14 +22,17 @@ Config option `filters` is an array. Each filter includes the following options:
* `enabled` => If true, this rule is enabled.
* `action` => What action to perform against the packet if matched. 0 = Block. 1 = Allow.
* `srcip` => The source IP to match (e.g. 10.50.0.3).
* `dstip` => The destination IP to match (e.g. 10.50.0.4).
* `min_ttl` => The minimum TTL (time to live) the packet has to match.
* `max_ttl` => The maximum TTL (time to live) the packet has to match.
* `max_len` => The maximum packet length the packet has to match. This includes the entire frame (ethernet header, IP header, L4 header, and data).
* `min_len` => The minimum packet length the packet has to match. This includes the entire frame (ethernet header, IP header, L4 header, and data).
* `tos` => The TOS (type of service) the packet has to match.
* `payloadmatch` => The payload (L4 data) the packet has to match. The format is in hexadecimal and each byte is separated by a space. An example includes: `FF FF FF FF 59`.
* `srcip` => The source IP the packet must have to match (e.g. 10.50.0.3).
* `dstip` => The destination IP the packet must have to match (e.g. 10.50.0.4).
* `min_ttl` => The minimum TTL (time to live) the packet must have to match.
* `max_ttl` => The maximum TTL (time to live) the packet must have to match.
* `max_len` => The maximum packet length the packet must have to match. This includes the entire frame (ethernet header, IP header, L4 header, and data).
* `min_len` => The minimum packet length the packet must have to match. This includes the entire frame (ethernet header, IP header, L4 header, and data).
* `tos` => The TOS (type of service) the packet must have to match.
* `pps` => The maximum packets per second a source IP can send before matching.
* `bps` => The maximum amount of bytes per second a source IP can send before matching.
* `blocktime` => The maximum of time in seconds to block the source IP if the rule matches and the action is block (0). Default value is `1`.
* `payloadmatch` => The payload (L4 data) the packet must have to match. The format is in hexadecimal and each byte is separated by a space. An example includes: `FF FF FF FF 59`.
#### TCP Options
The config option `tcpopts` within a filter is an array including TCP options. This should only be one array per filter. Options include:

12
src/config.c
View File

@@ -278,6 +278,18 @@ int ReadConfig(struct config_map *cfg)
cfg->filters[i].do_bps = 1;
}
// Block time (default 1).
int blocktime;
if (config_setting_lookup_int(filter, "blocktime", &blocktime))
{
cfg->filters[i].blockTime = blocktime;
}
else
{
cfg->filters[i].blockTime = 1;
}
// Payload match.
const char *payload;

2
src/include/xdpfw.h
View File

@@ -91,6 +91,8 @@ struct filter
unsigned int do_bps : 1;
uint64_t bps;
uint16_t blockTime;
uint8_t payloadMatch[MAX_PCKT_LENGTH];
uint16_t payloadLen;

679
src/xdpfw_kern.c
View File

@@ -66,6 +66,14 @@ struct bpf_map_def SEC("maps") ip_stats_map =
.max_entries = MAX_TRACK_IPS
};
struct bpf_map_def SEC("maps") ip_blacklist_map =
{
.type = BPF_MAP_TYPE_LRU_PERCPU_HASH,
.key_size = sizeof(uint32_t),
.value_size = sizeof(uint64_t),
.max_entries = MAX_TRACK_IPS
};
SEC("xdp_prog")
int xdp_prog_main(struct xdp_md *ctx)
{
@@ -82,6 +90,91 @@ int xdp_prog_main(struct xdp_md *ctx)
return XDP_DROP;
}
// Check Ethernet protocol.
if (unlikely(ethhdr->h_proto != htons(ETH_P_IP)))
{
return XDP_PASS;
}
uint8_t matched = 0;
uint8_t action = 0;
uint64_t blocktime = 1;
// Scan IP header.
struct iphdr *iph = data + sizeof(struct ethhdr);
// Check if the IP header is valid.
if (unlikely(iph + 1 > (struct iphdr *)data_end))
{
return XDP_DROP;
}
// Check IP header protocols.
if (unlikely(iph->protocol != IPPROTO_UDP && iph->protocol != IPPROTO_TCP && iph->protocol != IPPROTO_ICMP))
{
return XDP_DROP;
}
uint64_t now = bpf_ktime_get_ns();
// Check blacklist map.
uint64_t *blocked = bpf_map_lookup_elem(&ip_blacklist_map, &iph->saddr);
if (blocked != NULL && *blocked > 0)
{
#ifdef DEBUG
bpf_printk("Checking for blocked packet... Block time %" PRIu64 "\n", *blocked);
#endif
if (now > *blocked)
{
// Remove element from map.
bpf_map_delete_elem(&ip_blacklist_map, &iph->saddr);
}
else
{
// They're still blocked. Drop the packet.
return XDP_DROP;
}
}
// Update IP stats (PPS/BPS).
uint64_t pps = 0;
uint64_t bps = 0;
struct xdpfw_ip_stats *ip_stats = bpf_map_lookup_elem(&ip_stats_map, &iph->saddr);
if (ip_stats)
{
// Check for reset.
if ((now - ip_stats->tracking) > 1000000000)
{
ip_stats->pps = 0;
ip_stats->bps = 0;
ip_stats->tracking = now;
}
ip_stats->pps++;
ip_stats->bps += ctx->data_end - ctx->data;
pps = ip_stats->pps;
bps = ip_stats->bps;
}
else
{
// Create new entry.
struct xdpfw_ip_stats new;
new.pps = 1;
new.bps = ctx->data_end - ctx->data;
new.tracking = now;
pps = new.pps;
bps = new.bps;
bpf_map_update_elem(&ip_stats_map, &iph->saddr, &new, BPF_ANY);
}
// Let's get the filters we need.
struct filter *filter[MAX_FILTERS];
@@ -92,359 +185,305 @@ int xdp_prog_main(struct xdp_md *ctx)
filter[i] = bpf_map_lookup_elem(&filters_map, &key);
}
uint8_t matched = 0;
uint8_t action = 0;
struct tcphdr *tcph;
struct udphdr *udph;
struct icmphdr *icmph;
uint16_t l4headerLen = 0;
// Check Ethernet protocol and ensure it's IP.
if (likely(ethhdr->h_proto == htons(ETH_P_IP)))
// Check protocol.
if (iph->protocol == IPPROTO_TCP)
{
// Scan IP header.
struct iphdr *iph = data + sizeof(struct ethhdr);
// Scan TCP header.
tcph = (data + sizeof(struct ethhdr) + (iph->ihl * 4));
// Check if the IP header is valid.
if (unlikely(iph + 1 > (struct iphdr *)data_end))
{
return XDP_DROP;
}
// Check IP header protocols.
if (unlikely(iph->protocol != IPPROTO_UDP && iph->protocol != IPPROTO_TCP && iph->protocol != IPPROTO_ICMP))
// Check TCP header.
if (tcph + 1 > (struct tcphdr *)data_end)
{
return XDP_PASS;
}
// Update IP stats (PPS/BPS).
uint64_t pps = 0;
uint64_t bps = 0;
uint64_t now = bpf_ktime_get_ns();
// Set L4 Header length.
l4headerLen = sizeof(struct tcphdr);
}
else if (iph->protocol == IPPROTO_UDP)
{
// Scan UDP header.
udph = (data + sizeof(struct ethhdr) + (iph->ihl * 4));
struct xdpfw_ip_stats *ip_stats = bpf_map_lookup_elem(&ip_stats_map, &iph->saddr);
if (ip_stats)
// Check TCP header.
if (udph + 1 > (struct udphdr *)data_end)
{
// Check for reset.
if ((now - ip_stats->tracking) > 1e9)
{
ip_stats->pps = 0;
ip_stats->bps = 0;
ip_stats->tracking = now;
}
ip_stats->pps++;
ip_stats->bps += ctx->data_end - ctx->data;
pps = ip_stats->pps;
bps = ip_stats->bps;
}
else
{
// Create new entry.
struct xdpfw_ip_stats new;
new.pps = 1;
new.bps = ctx->data_end - ctx->data;
new.tracking = now;
pps = new.pps;
bps = new.bps;
bpf_map_update_elem(&ip_stats_map, &iph->saddr, &new, BPF_ANY);
return XDP_PASS;
}
struct tcphdr *tcph;
struct udphdr *udph;
struct icmphdr *icmph;
uint16_t l4headerLen = 0;
// Set L4 Header length.
l4headerLen = sizeof(struct udphdr);
}
else if (iph->protocol == IPPROTO_ICMP)
{
// Scan UDP header.
icmph = (data + sizeof(struct ethhdr) + (iph->ihl * 4));
// Check protocol.
if (iph->protocol == IPPROTO_TCP)
// Check TCP header.
if (icmph + 1 > (struct icmphdr *)data_end)
{
// Scan TCP header.
tcph = (data + sizeof(struct ethhdr) + (iph->ihl * 4));
// Check TCP header.
if (tcph + 1 > (struct tcphdr *)data_end)
{
return XDP_PASS;
}
// Set L4 Header length.
l4headerLen = sizeof(struct tcphdr);
return XDP_PASS;
}
else if (iph->protocol == IPPROTO_UDP)
// Set L4 Header length.
l4headerLen = sizeof(struct icmphdr);
}
for (uint8_t i = 0; i < MAX_FILTERS; i++)
{
// Check if ID is above 0 (if 0, it's an invalid rule).
if (!filter[i] || filter[i]->id < 1)
{
// Scan UDP header.
udph = (data + sizeof(struct ethhdr) + (iph->ihl * 4));
// Check TCP header.
if (udph + 1 > (struct udphdr *)data_end)
{
return XDP_PASS;
}
// Set L4 Header length.
l4headerLen = sizeof(struct udphdr);
}
else if (iph->protocol == IPPROTO_ICMP)
{
// Scan UDP header.
icmph = (data + sizeof(struct ethhdr) + (iph->ihl * 4));
// Check TCP header.
if (icmph + 1 > (struct icmphdr *)data_end)
{
return XDP_PASS;
}
// Set L4 Header length.
l4headerLen = sizeof(struct icmphdr);
}
for (uint8_t i = 0; i < MAX_FILTERS; i++)
{
// Check if ID is above 0 (if 0, it's an invalid rule).
if (!filter[i] || filter[i]->id < 1)
{
break;
}
// Check if the rule is enabled.
if (!filter[i]->enabled)
{
continue;
}
// Source address.
if (filter[i]->srcIP != 0 && iph->saddr != filter[i]->srcIP)
{
continue;
}
// Destination address.
if (filter[i]->dstIP != 0 && iph->daddr != filter[i]->dstIP)
{
continue;
}
// Max TTL length.
if (filter[i]->do_max_ttl && filter[i]->max_ttl > iph->ttl)
{
continue;
}
// Min TTL length.
if (filter[i]->do_min_ttl && filter[i]->min_ttl < iph->ttl)
{
continue;
}
// Max packet length.
if (filter[i]->do_max_len && filter[i]->max_len > (ntohs(iph->tot_len) + sizeof(struct ethhdr)))
{
continue;
}
// Min packet length.
if (filter[i]->do_min_len && filter[i]->min_len < (ntohs(iph->tot_len) + sizeof(struct ethhdr)))
{
continue;
}
// TOS.
if (filter[i]->do_tos && filter[i]->tos != iph->tos)
{
continue;
}
// PPS.
if (filter[i]->do_pps && pps <= filter[i]->pps)
{
continue;
}
// BPS.
if (filter[i]->do_bps && bps <= filter[i]->bps)
{
continue;
}
// Payload match.
/*
if (filter[i]->payloadLen > 0)
{
uint8_t found = 1;
// Initialize packet data.
for (uint16_t j = 0; j < MAX_PCKT_LENGTH; j++)
{
if ((j + 1) > filter[i]->payloadLen)
{
break;
}
uint8_t *byte = (data + sizeof(struct ethhdr) + (iph->ihl * 4) + l4headerLen + j);
if (byte + 1 > (uint8_t *)data_end)
{
break;
}
if (*byte == filter[i]->payloadMatch[j])
{
continue;
}
found = 0;
break;
}
if (!found)
{
continue;
}
}
*/
// Check layer 4 filters.
if (iph->protocol == IPPROTO_TCP && !filter[i]->tcpopts.enabled)
{
continue;
}
else if (iph->protocol == IPPROTO_UDP && !filter[i]->udpopts.enabled)
{
continue;
}
else if (iph->protocol == IPPROTO_ICMP && !filter[i]->icmpopts.enabled)
{
continue;
}
// Do TCP options.
if (iph->protocol == IPPROTO_TCP && filter[i]->tcpopts.enabled)
{
// Source port.
if (filter[i]->tcpopts.do_sport && htons(filter[i]->tcpopts.sport) != tcph->source)
{
continue;
}
// Destination port.
if (filter[i]->tcpopts.do_dport && htons(filter[i]->tcpopts.dport) != tcph->dest)
{
continue;
}
// URG flag.
if (filter[i]->tcpopts.do_urg && filter[i]->tcpopts.urg != tcph->urg)
{
continue;
}
// ACK flag.
if (filter[i]->tcpopts.do_ack && filter[i]->tcpopts.ack != tcph->ack)
{
continue;
}
// RST flag.
if (filter[i]->tcpopts.do_rst && filter[i]->tcpopts.rst != tcph->rst)
{
continue;
}
// PSH flag.
if (filter[i]->tcpopts.do_psh && filter[i]->tcpopts.psh != tcph->psh)
{
continue;
}
// SYN flag.
if (filter[i]->tcpopts.do_syn && filter[i]->tcpopts.syn != tcph->syn)
{
continue;
}
// FIN flag.
if (filter[i]->tcpopts.do_fin && filter[i]->tcpopts.fin != tcph->fin)
{
continue;
}
}
else if (iph->protocol == IPPROTO_UDP && filter[i]->udpopts.enabled)
{
// Source port.
if (filter[i]->udpopts.do_sport && htons(filter[i]->udpopts.sport) != udph->source)
{
continue;
}
// Destination port.
if (filter[i]->udpopts.do_dport && htons(filter[i]->udpopts.dport) != udph->dest)
{
continue;
}
}
else if (iph->protocol == IPPROTO_ICMP && filter[i]->icmpopts.enabled)
{
// Code.
if (filter[i]->icmpopts.do_code && filter[i]->icmpopts.code != icmph->code)
{
continue;
}
// Type.
if (filter[i]->icmpopts.do_type && filter[i]->icmpopts.type != icmph->type)
{
continue;
}
}
// Matched.
#ifdef DEBUG
bpf_printk("Matched rule ID #%" PRIu8 ".\n", filter[i]->id);
#endif
matched = 1;
action = filter[i]->action;
break;
}
if (matched)
// Check if the rule is enabled.
if (!filter[i]->enabled)
{
// Get stats map.
uint32_t key = 0;
struct xdpfw_stats *stats;
continue;
}
stats = bpf_map_lookup_elem(&stats_map, &key);
// Source address.
if (filter[i]->srcIP != 0 && iph->saddr != filter[i]->srcIP)
{
continue;
}
if (stats)
// Destination address.
if (filter[i]->dstIP != 0 && iph->daddr != filter[i]->dstIP)
{
continue;
}
// Max TTL length.
if (filter[i]->do_max_ttl && filter[i]->max_ttl > iph->ttl)
{
continue;
}
// Min TTL length.
if (filter[i]->do_min_ttl && filter[i]->min_ttl < iph->ttl)
{
continue;
}
// Max packet length.
if (filter[i]->do_max_len && filter[i]->max_len > (ntohs(iph->tot_len) + sizeof(struct ethhdr)))
{
continue;
}
// Min packet length.
if (filter[i]->do_min_len && filter[i]->min_len < (ntohs(iph->tot_len) + sizeof(struct ethhdr)))
{
continue;
}
// TOS.
if (filter[i]->do_tos && filter[i]->tos != iph->tos)
{
continue;
}
// PPS.
if (filter[i]->do_pps && pps <= filter[i]->pps)
{
continue;
}
// BPS.
if (filter[i]->do_bps && bps <= filter[i]->bps)
{
continue;
}
// Payload match.
/*
if (filter[i]->payloadLen > 0)
{
uint8_t found = 1;
// Initialize packet data.
for (uint16_t j = 0; j < MAX_PCKT_LENGTH; j++)
{
// Update stats map.
if (action == 0)
if ((j + 1) > filter[i]->payloadLen)
{
stats->blocked++;
}
else
{
stats->allowed++;
break;
}
key = 0;
uint8_t *byte = (data + sizeof(struct ethhdr) + (iph->ihl * 4) + l4headerLen + j);
bpf_map_update_elem(&stats_map, &key, stats, BPF_ANY);
if (byte + 1 > (uint8_t *)data_end)
{
break;
}
if (*byte == filter[i]->payloadMatch[j])
{
continue;
}
found = 0;
break;
}
#ifdef DEBUG
//bpf_printk("Matched with protocol %" PRIu8 " and sAddr %" PRIu32 ".\n", iph->protocol, iph->saddr);
#endif
if (!found)
{
continue;
}
}
*/
// Check layer 4 filters.
if (iph->protocol == IPPROTO_TCP && !filter[i]->tcpopts.enabled)
{
continue;
}
else if (iph->protocol == IPPROTO_UDP && !filter[i]->udpopts.enabled)
{
continue;
}
else if (iph->protocol == IPPROTO_ICMP && !filter[i]->icmpopts.enabled)
{
continue;
}
// Do TCP options.
if (iph->protocol == IPPROTO_TCP && filter[i]->tcpopts.enabled)
{
// Source port.
if (filter[i]->tcpopts.do_sport && htons(filter[i]->tcpopts.sport) != tcph->source)
{
continue;
}
// Destination port.
if (filter[i]->tcpopts.do_dport && htons(filter[i]->tcpopts.dport) != tcph->dest)
{
continue;
}
// URG flag.
if (filter[i]->tcpopts.do_urg && filter[i]->tcpopts.urg != tcph->urg)
{
continue;
}
// ACK flag.
if (filter[i]->tcpopts.do_ack && filter[i]->tcpopts.ack != tcph->ack)
{
continue;
}
// RST flag.
if (filter[i]->tcpopts.do_rst && filter[i]->tcpopts.rst != tcph->rst)
{
continue;
}
// PSH flag.
if (filter[i]->tcpopts.do_psh && filter[i]->tcpopts.psh != tcph->psh)
{
continue;
}
// SYN flag.
if (filter[i]->tcpopts.do_syn && filter[i]->tcpopts.syn != tcph->syn)
{
continue;
}
// FIN flag.
if (filter[i]->tcpopts.do_fin && filter[i]->tcpopts.fin != tcph->fin)
{
continue;
}
}
else if (iph->protocol == IPPROTO_UDP && filter[i]->udpopts.enabled)
{
// Source port.
if (filter[i]->udpopts.do_sport && htons(filter[i]->udpopts.sport) != udph->source)
{
continue;
}
// Destination port.
if (filter[i]->udpopts.do_dport && htons(filter[i]->udpopts.dport) != udph->dest)
{
continue;
}
}
else if (iph->protocol == IPPROTO_ICMP && filter[i]->icmpopts.enabled)
{
// Code.
if (filter[i]->icmpopts.do_code && filter[i]->icmpopts.code != icmph->code)
{
continue;
}
// Type.
if (filter[i]->icmpopts.do_type && filter[i]->icmpopts.type != icmph->type)
{
continue;
}
}
// Matched.
#ifdef DEBUG
bpf_printk("Matched rule ID #%" PRIu8 ".\n", filter[i]->id);
#endif
matched = 1;
action = filter[i]->action;
blocktime = filter[i]->blockTime;
break;
}
if (matched)
{
// Get stats map.
uint32_t key = 0;
struct xdpfw_stats *stats;
stats = bpf_map_lookup_elem(&stats_map, &key);
if (stats)
{
// Update stats map.
if (action == 0)
{
stats->blocked++;
}
else
{
stats->allowed++;
}
key = 0;
bpf_map_update_elem(&stats_map, &key, stats, BPF_ANY);
}
#ifdef DEBUG
//bpf_printk("Matched with protocol %" PRIu8 " and sAddr %" PRIu32 ".\n", iph->protocol, iph->saddr);
#endif
}
if (matched && action == 0)
{
// Before dropping, update the blacklist map.
uint64_t newTime = now + (blocktime * 1000000000);
bpf_map_update_elem(&ip_blacklist_map, &iph->saddr, &newTime, BPF_ANY);
return XDP_DROP;
}

1
src/xdpfw_loader.c
View File

@@ -344,6 +344,7 @@ int main(int argc, char *argv[])
fprintf(stdout, "TOS => %" PRIu8 "\n", conf->filters[i].tos);
fprintf(stdout, "PPS => %" PRIu64 "\n", conf->filters[i].pps);
fprintf(stdout, "BPS => %" PRIu64 "\n\n", conf->filters[i].bps);
fprintf(stdout, "Block Time => %" PRIu16 "\n\n", conf->filters[i].blockTime);
// TCP Options.
fprintf(stdout, "TCP Enabled => %" PRIu8 "\n", conf->filters[i].tcpopts.enabled);