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Add eBPF C code linter #314

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Apr 12, 2024
Merged

Add eBPF C code linter #314

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4 changes: 3 additions & 1 deletion Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -112,8 +112,10 @@ fmt: ## Run go fmt against code.

.PHONY: lint
lint: prereqs ## Lint the code
@echo "### Linting code"
@echo "### Linting golang code"
golangci-lint run ./... --timeout=3m
@echo "### Linting bpf C code"
find ./bpf -type f -not -path "./bpf/headers/*" -name "*.[ch]" | xargs clang-format --dry-run --Werror

.PHONY: gen-bpf
gen-bpf: export BPF_CLANG := $(CLANG)
Expand Down
56 changes: 28 additions & 28 deletions bpf/dns_tracker.h
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Original file line number Diff line number Diff line change
Expand Up @@ -6,10 +6,10 @@
#define __DNS_TRACKER_H__
#include "utils.h"

#define DNS_PORT 53
#define DNS_QR_FLAG 0x8000
#define UDP_MAXMSG 512
#define EINVAL 22
#define DNS_PORT 53
#define DNS_QR_FLAG 0x8000
#define UDP_MAXMSG 512
#define EINVAL 22

struct dns_header {
u16 id;
Expand All @@ -20,7 +20,7 @@ struct dns_header {
u16 arcount;
};

static inline void fill_dns_id (flow_id *id, dns_flow_id *dns_flow, u16 dns_id, bool reverse) {
static inline void fill_dns_id(flow_id *id, dns_flow_id *dns_flow, u16 dns_id, bool reverse) {
dns_flow->id = dns_id;
dns_flow->protocol = id->transport_protocol;
if (reverse) {
Expand All @@ -39,28 +39,28 @@ static inline void fill_dns_id (flow_id *id, dns_flow_id *dns_flow, u16 dns_id,
static __always_inline u8 calc_dns_header_offset(pkt_info *pkt, void *data_end) {
u8 len = 0;
switch (pkt->id->transport_protocol) {
case IPPROTO_TCP: {
struct tcphdr *tcp = (struct tcphdr *) pkt->l4_hdr;
if (!tcp || ((void *)tcp + sizeof(*tcp) > data_end)) {
return 0;
}
len = tcp->doff * sizeof(u32) + 2; // DNS over TCP has 2 bytes of length at the beginning
break;
case IPPROTO_TCP: {
struct tcphdr *tcp = (struct tcphdr *)pkt->l4_hdr;
if (!tcp || ((void *)tcp + sizeof(*tcp) > data_end)) {
return 0;
}
case IPPROTO_UDP: {
struct udphdr *udp = (struct udphdr *) pkt->l4_hdr;
if (!udp || ((void *)udp + sizeof(*udp) > data_end)) {
return 0;
}
len = bpf_ntohs(udp->len);
// make sure udp payload doesn't exceed max msg size
if (len - sizeof(struct udphdr) > UDP_MAXMSG) {
return 0;
}
// set the length to udp hdr size as it will be used to locate dns header
len = sizeof(struct udphdr);
break;
len = tcp->doff * sizeof(u32) + 2; // DNS over TCP has 2 bytes of length at the beginning
break;
}
case IPPROTO_UDP: {
struct udphdr *udp = (struct udphdr *)pkt->l4_hdr;
if (!udp || ((void *)udp + sizeof(*udp) > data_end)) {
return 0;
}
len = bpf_ntohs(udp->len);
// make sure udp payload doesn't exceed max msg size
if (len - sizeof(struct udphdr) > UDP_MAXMSG) {
return 0;
}
// set the length to udp hdr size as it will be used to locate dns header
len = sizeof(struct udphdr);
break;
}
}
return len;
}
Expand Down Expand Up @@ -95,14 +95,14 @@ static __always_inline int track_dns_packet(struct __sk_buff *skb, pkt_info *pkt
} else { /* dns response */
fill_dns_id(pkt->id, &dns_req, dns_id, true);
u64 *value = bpf_map_lookup_elem(&dns_flows, &dns_req);
if (value != NULL) {
if (value != NULL) {
pkt->dns_latency = ts - *value;
pkt->dns_id = dns_id;
pkt->dns_flags = flags;
bpf_map_delete_elem(&dns_flows, &dns_req);
}
}
} // end of dns response
} // end of dns port check
} // end of dns port check
return 0;
}

Expand Down
10 changes: 5 additions & 5 deletions bpf/flows.c
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Original file line number Diff line number Diff line change
Expand Up @@ -72,9 +72,9 @@ static inline int flow_monitor(struct __sk_buff *skb, u8 direction) {

// check if this packet need to be filtered if filtering feature is enabled
if (enable_flows_filtering) {
u32* filter_counter_p = NULL;
u32 *filter_counter_p = NULL;
u32 initVal = 1, key = 0;
if (is_flow_filtered(&id, &action) != 0 && action != MAX_FILTER_ACTIONS) {
if (is_flow_filtered(&id, &action) != 0 && action != MAX_FILTER_ACTIONS) {
// we have matching rules follow through the actions to decide if we should accept or reject the flow
// and update global counter for both cases
u32 reject_key = FILTER_FLOWS_REJECT_KEY, accept_key = FILTER_FLOWS_ACCEPT_KEY;
Expand Down Expand Up @@ -116,7 +116,7 @@ static inline int flow_monitor(struct __sk_buff *skb, u8 direction) {
if (action == ACCEPT || action == MAX_FILTER_ACTIONS) {
return TC_ACT_OK;
} else {
// we have reject rule and no match so we can add the flows to the hashmap table.
// we have reject rule and no match so we can add the flows to the hashmap table.
}
}
}
Expand Down Expand Up @@ -197,7 +197,8 @@ static inline int flow_monitor(struct __sk_buff *skb, u8 direction) {
}

new_flow.errno = -ret;
flow_record *record = (flow_record *)bpf_ringbuf_reserve(&direct_flows, sizeof(flow_record), 0);
flow_record *record =
(flow_record *)bpf_ringbuf_reserve(&direct_flows, sizeof(flow_record), 0);
if (!record) {
if (trace_messages) {
bpf_printk("couldn't reserve space in the ringbuf. Dropping flow");
Expand All @@ -223,4 +224,3 @@ int egress_flow_parse(struct __sk_buff *skb) {
}

char _license[] SEC("license") = "GPL";

16 changes: 9 additions & 7 deletions bpf/flows_filter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -32,11 +32,11 @@ static __always_inline int is_equal_ip(u8 *ip1, u8 *ip2, u8 len) {
return 0;
}
}
return 1;
return 1;
}

static __always_inline int do_flow_filter_lookup(flow_id *id, struct filter_key_t *key, filter_action *action,
u8 len, u8 offset) {
static __always_inline int do_flow_filter_lookup(flow_id *id, struct filter_key_t *key,
filter_action *action, u8 len, u8 offset) {
int result = 0;

struct filter_value_t *rule = (struct filter_value_t *)bpf_map_lookup_elem(&filter_map, key);
Expand Down Expand Up @@ -68,7 +68,8 @@ static __always_inline int do_flow_filter_lookup(flow_id *id, struct filter_key_
goto end;
}
} else if (rule->dstPortStart != 0 && rule->dstPortEnd != 0) {
if (rule->dstPortStart <= id->dst_port && id->dst_port <= rule->dstPortEnd) {
if (rule->dstPortStart <= id->dst_port &&
id->dst_port <= rule->dstPortEnd) {
BPF_PRINTK("dstPortStart and dstPortEnd matched\n");
result++;
} else {
Expand All @@ -86,7 +87,8 @@ static __always_inline int do_flow_filter_lookup(flow_id *id, struct filter_key_
goto end;
}
} else if (rule->srcPortStart != 0 && rule->srcPortEnd != 0) {
if (rule->srcPortStart <= id->src_port && id->src_port <= rule->srcPortEnd) {
if (rule->srcPortStart <= id->src_port &&
id->src_port <= rule->srcPortEnd) {
BPF_PRINTK("srcPortStart and srcPortEnd matched\n");
result++;
} else {
Expand Down Expand Up @@ -137,8 +139,8 @@ static __always_inline int do_flow_filter_lookup(flow_id *id, struct filter_key_
break;
}
} else {
result = 0;
goto end;
result = 0;
goto end;
}
}

Expand Down
6 changes: 3 additions & 3 deletions bpf/maps_definition.h
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Original file line number Diff line number Diff line change
Expand Up @@ -21,16 +21,16 @@ struct {
//PerfEvent Array for Packet Payloads
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__type(key, u32);
__type(value, u32);
__type(key, u32);
__type(value, u32);
__uint(max_entries, 256);
} packet_record SEC(".maps");

// DNS tracking flow based hashmap used to correlate query and responses
// to allow calculating latency in ebpf agent directly
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, 1 << 20); // Will take around 64MB of space.
__uint(max_entries, 1 << 20); // Will take around 64MB of space.
__type(key, dns_flow_id);
__type(value, u64);
__uint(map_flags, BPF_F_NO_PREALLOC);
Expand Down
114 changes: 55 additions & 59 deletions bpf/pca.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3,119 +3,115 @@

#include "utils.h"

static int attach_packet_payload(void *data, void *data_end, struct __sk_buff *skb){
payload_meta meta;
u64 flags = BPF_F_CURRENT_CPU;
// Enable the flag to add packet header
// Packet payload follows immediately after the meta struct
u32 packetSize = (u32)(data_end-data);
// Record the current time.
u64 current_time = bpf_ktime_get_ns();
// For packets which are allocated non-linearly struct __sk_buff does not necessarily
// has all data lined up in memory but instead can be part of scatter gather lists.
// This command pulls data from the buffer but incurs data copying penalty.
if (packetSize <= skb->len){
packetSize = skb->len;
if (bpf_skb_pull_data(skb, skb->len)){
return TC_ACT_UNSPEC;
};
}
// Set flag's upper 32 bits with the size of the paylaod and the bpf_perf_event_output will
// attach the specified amount of bytes from packet to the perf event
// https://github.com/xdp-project/xdp-tutorial/tree/9b25f0a039179aca1f66cba5492744d9f09662c1/tracing04-xdp-tcpdump
flags |= (u64)packetSize << 32;

meta.if_index = skb->ifindex;
meta.pkt_len = packetSize;
meta.timestamp = current_time;
if (bpf_perf_event_output(skb, &packet_record, flags, &meta, sizeof(meta))){
return TC_ACT_OK;
}
return TC_ACT_UNSPEC;
static int attach_packet_payload(void *data, void *data_end, struct __sk_buff *skb) {
payload_meta meta;
u64 flags = BPF_F_CURRENT_CPU;
// Enable the flag to add packet header
// Packet payload follows immediately after the meta struct
u32 packetSize = (u32)(data_end - data);

// Record the current time.
u64 current_time = bpf_ktime_get_ns();

// For packets which are allocated non-linearly struct __sk_buff does not necessarily
// has all data lined up in memory but instead can be part of scatter gather lists.
// This command pulls data from the buffer but incurs data copying penalty.
if (packetSize <= skb->len) {
packetSize = skb->len;
if (bpf_skb_pull_data(skb, skb->len)) {
return TC_ACT_UNSPEC;
};
}
// Set flag's upper 32 bits with the size of the paylaod and the bpf_perf_event_output will
// attach the specified amount of bytes from packet to the perf event
// https://github.com/xdp-project/xdp-tutorial/tree/9b25f0a039179aca1f66cba5492744d9f09662c1/tracing04-xdp-tcpdump
flags |= (u64)packetSize << 32;

meta.if_index = skb->ifindex;
meta.pkt_len = packetSize;
meta.timestamp = current_time;
if (bpf_perf_event_output(skb, &packet_record, flags, &meta, sizeof(meta))) {
return TC_ACT_OK;
}
return TC_ACT_UNSPEC;
}

static inline bool validate_pca_filter(u8 ipproto, void *ipheaderend, void *data_end){
static inline bool validate_pca_filter(u8 ipproto, void *ipheaderend, void *data_end) {
// If filters: pca_proto and pca_port are not specified, export packet
if (pca_proto == 0 && pca_port == 0)
return true;

//Only export packets with protocol set by ENV var PCA_FILTER
u16 sourcePort, destPort;
if (ipproto != pca_proto) {
return false;
return false;
}

if (ipproto == IPPROTO_TCP){
if (ipproto == IPPROTO_TCP) {
struct tcphdr *tcp_header = ipheaderend;
if ((void *)tcp_header + sizeof(*tcp_header) > data_end) {
return false;
}
sourcePort = tcp_header->source;
destPort = tcp_header->dest;
}
else if (ipproto == IPPROTO_UDP){
} else if (ipproto == IPPROTO_UDP) {
struct udphdr *udp_header = ipheaderend;
if ((void *)udp_header + sizeof(*udp_header) > data_end) {
return false;
return false;
}
sourcePort = udp_header->source;
destPort = udp_header->dest;
}
else if (ipproto == IPPROTO_SCTP){
} else if (ipproto == IPPROTO_SCTP) {
struct sctphdr *sctp_header = ipheaderend;
if ((void *)sctp_header + sizeof(*sctp_header) > data_end) {
return false;
}
sourcePort = sctp_header->source;
destPort = sctp_header->dest;
}
else {
return false;
}
sourcePort = sctp_header->source;
destPort = sctp_header->dest;
} else {
return false;
}
u16 pca_port_end = bpf_htons(pca_port);
if (sourcePort == pca_port_end || destPort == pca_port_end){
if (sourcePort == pca_port_end || destPort == pca_port_end) {
return true;
}
return false;
}

static inline int export_packet_payload (struct __sk_buff *skb) {
static inline int export_packet_payload(struct __sk_buff *skb) {
void *data_end = (void *)(long)skb->data_end;
void *data = (void *)(long)skb->data;
struct ethhdr *eth = data;
struct iphdr *ip;
struct ethhdr *eth = data;
struct iphdr *ip;

if ((void *)eth + sizeof(*eth) > data_end) {
return TC_ACT_UNSPEC;
return TC_ACT_UNSPEC;
}

// Only IPv4 and IPv6 packets captured
u16 ethType = bpf_ntohs(eth->h_proto);
if (ethType != ETH_P_IP && ethType != ETH_P_IPV6) {
return TC_ACT_UNSPEC;
}
return TC_ACT_UNSPEC;
}

ip = data + sizeof(*eth);
if ((void *)ip + sizeof(*ip) > data_end) {
return TC_ACT_UNSPEC;
return TC_ACT_UNSPEC;
}

if (validate_pca_filter(ip->protocol, (void *)ip + sizeof(*ip), data_end )){
if (validate_pca_filter(ip->protocol, (void *)ip + sizeof(*ip), data_end)) {
return attach_packet_payload(data, data_end, skb);
}
return TC_ACT_UNSPEC;
}


SEC("tc_pca_ingress")
int ingress_pca_parse (struct __sk_buff *skb) {
int ingress_pca_parse(struct __sk_buff *skb) {
return export_packet_payload(skb);
}

SEC("tc_pca_egress")
int egress_pca_parse (struct __sk_buff *skb) {
int egress_pca_parse(struct __sk_buff *skb) {
return export_packet_payload(skb);
}

Expand Down
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