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Merged
grcevski merged 2 commits into from
Feb 27, 2026
Merged

gotracer: set trace context in shared map for http and other protocols #1370

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e02c1ee
gotracer: set trace context in shared map for http and other protocols
mmat11 Feb 26, 2026
a4c2d78
apply review suggestions
mmat11 Feb 27, 2026
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12 changes: 5 additions & 7 deletions bpf/gotracer/go_common.h
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Expand Up @@ -27,12 +27,17 @@

#include <gotracer/go_offsets.h>

#include <gotracer/maps/mongo.h>

#include <logger/bpf_dbg.h>

char __license[] SEC("license") = "Dual MIT/GPL";

enum { W3C_KEY_LENGTH = 11, W3C_VAL_LENGTH = 55 };

static unsigned char tp_encoded[] = {
0x4d, 0x83, 0x21, 0x6b, 0x1d, 0x85, 0xa9, 0x3f}; // hpack encoded "traceparent"

// Temporary information about a function invocation. It stores the invocation time of a function
// as well as the value of registers at the invocation time. This way we can retrieve them at the
// return uprobes so we can know the values of the function arguments (which are passed as registers
Expand Down Expand Up @@ -119,13 +124,6 @@ struct {
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} ongoing_sql_queries SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // key: goroutine id
__type(value, mongo_go_client_req_t); // the request
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} ongoing_mongo_requests SEC(".maps");

typedef struct grpc_header_field {
u8 *key_ptr;
u64 key_len;
Expand Down
5 changes: 2 additions & 3 deletions bpf/gotracer/go_grpc.c
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Expand Up @@ -23,7 +23,6 @@
#include <gotracer/go_common.h>
#include <gotracer/go_offsets.h>
#include <gotracer/go_str.h>
#include <gotracer/hpack.h>

#include <gotracer/maps/grpc.h>

Expand Down Expand Up @@ -826,7 +825,7 @@ int obi_uprobe_grpcFramerWriteHeaders_returns(struct pt_regs *ctx) {
if (original_size > 0) {
u8 type_byte = 0;
const u8 key_len =
TP_ENCODED_LEN | 0x80; // high tagged to signify hpack encoded value
sizeof(tp_encoded) | 0x80; // high tagged to signify hpack encoded value
const u8 val_len = TP_MAX_VAL_LENGTH;

// We don't hpack encode the value of the traceparent field, because that will require that
Expand All @@ -842,7 +841,7 @@ int obi_uprobe_grpcFramerWriteHeaders_returns(struct pt_regs *ctx) {
// Write 'traceparent' encoded as hpack
bpf_probe_write_user(buf_arr + (n & 0x0ffff), tp_encoded, sizeof(tp_encoded));
;
n += TP_ENCODED_LEN;
n += sizeof(tp_encoded);
// Write the length of the hpack encoded traceparent field
bpf_probe_write_user(buf_arr + (n & 0x0ffff), &val_len, sizeof(val_len));
n++;
Expand Down
18 changes: 0 additions & 18 deletions bpf/gotracer/go_kafka_def.h
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This file was deleted.

61 changes: 12 additions & 49 deletions bpf/gotracer/go_kafka_go.c
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Expand Up @@ -17,58 +17,16 @@

#include <bpfcore/utils.h>

#include <common/common.h>
#include <common/ringbuf.h>

#include <gotracer/go_common.h>
#include <gotracer/go_kafka_def.h>

#include <logger/bpf_dbg.h>
#include <gotracer/maps/kafka.h>

#include <gotracer/types/kafka.h>

typedef struct produce_req {
u64 msg_ptr;
u64 conn_ptr;
u64 start_monotime_ns;
} produce_req_t;

typedef struct topic {
char name[MAX_TOPIC_NAME_LEN];
tp_info_t tp;
} topic_t;

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // w_ptr
__type(value, tp_info_t); // traceparent
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} produce_traceparents SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // goroutine
__type(value, topic_t); // topic info
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} ongoing_produce_topics SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // msg ptr
__type(value, topic_t); // topic info
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} ongoing_produce_messages SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // goroutine
__type(value, produce_req_t); // rw ptr + start time
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} produce_requests SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // goroutine
__type(value, kafka_go_req_t); // rw ptr + start time
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} fetch_requests SEC(".maps");
#include <logger/bpf_dbg.h>

// Code for the produce messages path
SEC("uprobe/writer_write_messages")
Expand All @@ -84,7 +42,12 @@ int obi_uprobe_writer_write_messages(struct pt_regs *ctx) {
go_addr_key_t p_key = {};
go_addr_key_from_id(&p_key, w_ptr);

go_addr_key_t g_key = {};
go_addr_key_from_id(&g_key, goroutine_addr);

bpf_map_update_elem(&produce_traceparents, &p_key, &tp, BPF_ANY);
bpf_map_update_elem(&produce_traceparents_by_goroutine, &g_key, &tp, BPF_ANY);

return 0;
}

Expand Down Expand Up @@ -223,7 +186,7 @@ int obi_uprobe_protocol_roundtrip_ret(struct pt_regs *ctx) {
kafka_go_req_t *trace = bpf_ringbuf_reserve(&events, sizeof(kafka_go_req_t), 0);
if (trace) {
trace->type = EVENT_GO_KAFKA_SEG;
trace->op = KAFKA_API_PRODUCE;
trace->op = k_kafka_api_produce;
trace->start_monotime_ns = p_ptr->start_monotime_ns;
trace->end_monotime_ns = bpf_ktime_get_ns();

Expand Down Expand Up @@ -269,7 +232,7 @@ int obi_uprobe_reader_read(struct pt_regs *ctx) {
if (r_ptr) {
kafka_go_req_t r = {
.type = EVENT_GO_KAFKA_SEG,
.op = KAFKA_API_FETCH,
.op = k_kafka_api_fetch,
.start_monotime_ns = 0,
};

Expand Down
3 changes: 3 additions & 0 deletions bpf/gotracer/go_mongo.c
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Expand Up @@ -17,11 +17,14 @@

#include <bpfcore/utils.h>

#include <common/common.h>
#include <common/ringbuf.h>

#include <gotracer/go_common.h>
#include <gotracer/go_str.h>

#include <gotracer/maps/mongo.h>

#include <logger/bpf_dbg.h>

#define MONGO_OP_DEF(name, str) \
Expand Down
6 changes: 5 additions & 1 deletion bpf/gotracer/go_net.c
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Expand Up @@ -20,8 +20,12 @@
#include <bpfcore/utils.h>
#include <bpfcore/bpf_builtins.h>

#include <common/common.h>

#include <gotracer/go_common.h>

#include <gotracer/maps/mongo.h>

#include <logger/bpf_dbg.h>

SEC("uprobe/netFdRead")
Expand Down Expand Up @@ -85,4 +89,4 @@ int obi_uprobe_netFdRead(struct pt_regs *ctx) {
}

return 0;
}
}
97 changes: 5 additions & 92 deletions bpf/gotracer/go_nethttp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -27,8 +27,10 @@
#include <gotracer/go_common.h>
#include <gotracer/go_offsets.h>
#include <gotracer/go_str.h>
#include <gotracer/hpack.h>

#include <gotracer/maps/nethttp.h>

#include <gotracer/types/nethttp.h>
#include <gotracer/types/stream_key.h>

#include <logger/bpf_dbg.h>
Expand All @@ -39,64 +41,11 @@

#include <pid/pid_helpers.h>

static const char traceparent[] = "traceparent: ";

static __always_inline unsigned char *tp_char_buf() {
int zero = 0;
return bpf_map_lookup_elem(&tp_char_buf_mem, &zero);
}

typedef struct http_client_data {
s64 content_length;
pid_info pid;
unsigned char path[PATH_MAX_LEN];
unsigned char host[HOST_MAX_LEN];
unsigned char scheme[SCHEME_MAX_LEN];
unsigned char method[METHOD_MAX_LEN];
u8 _pad[3];
} http_client_data_t;

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // key: pointer to the request goroutine
__type(value, http_client_data_t);
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} ongoing_http_client_requests_data SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // key: pointer to the request goroutine
__type(value, tp_info_t);
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} http2_server_requests_tp SEC(".maps");

typedef struct server_http_func_invocation {
u64 start_monotime_ns;
u64 content_length;
u64 response_length;
u64 status;
u64 rpc_request_addr; // pointer to the jsonrpc Request
tp_info_t tp;
u8 method[METHOD_MAX_LEN];
u8 path[PATH_MAX_LEN];
u8 pattern[PATTERN_MAX_LEN];
u8 _pad[5];
} server_http_func_invocation_t;

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // key: pointer to the request goroutine
__type(value, server_http_func_invocation_t);
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} ongoing_http_server_requests SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__type(key, u32);
__type(value, unsigned char[HTTP_HEADER_MAX_LEN]);
__uint(max_entries, 1);
} temp_header_mem_store SEC(".maps");

static __always_inline unsigned char *temp_header_mem() {
const u32 zero = 0;
return bpf_map_lookup_elem(&temp_header_mem_store, &zero);
Expand Down Expand Up @@ -636,13 +585,6 @@ int obi_uprobe_ServeHTTPReturns(struct pt_regs *ctx) {
return serve_http_returns(ctx);
}

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, void *); // key: pointer to the request header map
__type(value, u64); // the goroutine of the transport request
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} header_req_map SEC(".maps");

/* HTTP Client. We expect to see HTTP client in both HTTP server and gRPC server calls.*/
static __always_inline void roundTripStartHelper(struct pt_regs *ctx) {
void *goroutine_addr = GOROUTINE_PTR(ctx);
Expand Down Expand Up @@ -1032,15 +974,6 @@ int obi_uprobe_http2serverConn_runHandler(struct pt_regs *ctx) {
return 0;
}

// HTTP 2.0 client support
struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, stream_key_t); // key: stream id + connection info
// the goroutine of the round trip request, which is the key for our traceparent info
__type(value, u64);
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} http2_req_map SEC(".maps");

static __always_inline void setup_http2_client_conn(void *goroutine_addr,
void *cc_ptr,
u32 stream_id,
Expand Down Expand Up @@ -1145,23 +1078,6 @@ int obi_uprobe_http2WriteHeaders_vendored(struct pt_regs *ctx) {
return 0;
}

#define MAX_W_PTR_N 1024

typedef struct framer_func_invocation {
u64 framer_ptr;
tp_info_t tp;
s64 initial_n;
} framer_func_invocation_t;

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // key: go routine doing framer write headers
__type(
value,
framer_func_invocation_t); // the goroutine of the round trip request, which is the key for our traceparent info
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} framer_invocation_map SEC(".maps");

static __always_inline void
on_http2FramerWriteHeaders(struct pt_regs *ctx, off_table_t *ot, u64 stream_id) {
if (!g_bpf_header_propagation) {
Expand Down Expand Up @@ -1273,9 +1189,6 @@ int obi_uprobe_net_http2FramerWriteHeaders(struct pt_regs *ctx) {
return 0;
}

#define HTTP2_ENCODED_HEADER_LEN \
66 // 1 + 1 + 8 + 1 + 55 = type byte + hpack_len_as_byte("traceparent") + strlen(hpack("traceparent")) + len_as_byte(55) + generated traceparent id

SEC("uprobe/http2FramerWriteHeaders_returns")
int obi_uprobe_http2FramerWriteHeaders_returns(struct pt_regs *ctx) {
if (!g_bpf_header_propagation) {
Expand Down Expand Up @@ -1348,7 +1261,7 @@ int obi_uprobe_http2FramerWriteHeaders_returns(struct pt_regs *ctx) {
if (original_size > 0) {
u8 type_byte = 0;
const u8 key_len =
TP_ENCODED_LEN | 0x80; // high tagged to signify hpack encoded value
sizeof(tp_encoded) | 0x80; // high tagged to signify hpack encoded value
const u8 val_len = TP_MAX_VAL_LENGTH;

// We don't hpack encode the value of the traceparent field, because that will require that
Expand All @@ -1364,7 +1277,7 @@ int obi_uprobe_http2FramerWriteHeaders_returns(struct pt_regs *ctx) {
// Write 'traceparent' encoded as hpack
bpf_probe_write_user(buf_arr + (n & 0x0ffff), tp_encoded, sizeof(tp_encoded));
;
n += TP_ENCODED_LEN;
n += sizeof(tp_encoded);
// Write the length of the hpack encoded traceparent field
bpf_probe_write_user(buf_arr + (n & 0x0ffff), &val_len, sizeof(val_len));
n++;
Expand Down
16 changes: 2 additions & 14 deletions bpf/gotracer/go_redis.c
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Expand Up @@ -21,21 +21,9 @@

#include <gotracer/go_common.h>

#include <logger/bpf_dbg.h>
#include <gotracer/maps/redis.h>

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // key: goroutine id
__type(value, redis_client_req_t); // the request
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} ongoing_redis_requests SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, go_addr_key_t); // key: goroutine id
__type(value, void *); // the *Conn
__uint(max_entries, MAX_CONCURRENT_REQUESTS);
} redis_writes SEC(".maps");
#include <logger/bpf_dbg.h>

static __always_inline void setup_request(void *goroutine_addr) {
redis_client_req_t req = {
Expand Down
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