fix: ebpf tailcall segmentation output

Author: kylewanginchina

agent/src/ebpf/kernel/files_rw.bpf.c

@@ -427,13 +427,19 @@ static __inline int trace_io_event_common(void *ctx,
 	v->msg_type = MSG_COMMON;
 	bpf_get_current_comm(v->comm, sizeof(v->comm));
 #if !defined(LINUX_VER_KFUNC) && !defined(LINUX_VER_5_2_PLUS)
-	struct tail_calls_context *context =
-	    (struct tail_calls_context *)v->data;
+	struct ctx_info_s *ctx_map = bpf_map_lookup_elem(&NAME(ctx_info), &k0);
+	if (!ctx_map) {
+		__sync_fetch_and_add(&tracer_ctx->push_buffer_refcnt, -1);
+		return -1;
+	}
+	struct tail_calls_context *context = &ctx_map->tail_call;
 	context->max_size_limit = data_max_sz;
 	context->push_reassembly_bytes = 0;
 	context->vecs = false;
 	context->is_close = false;
 	context->dir = direction;
+	context->sent_bytes = 0;
+	context->bytes_remaining = 0;
 #ifdef SUPPORTS_KPROBE_ONLY
 	bpf_tail_call(ctx, &NAME(progs_jmp_kp_map), PROG_OUTPUT_DATA_KP_IDX);
 #else
@@ -442,7 +448,7 @@ static __inline int trace_io_event_common(void *ctx,
 	return 0;
 #else
 	return __output_data_common(ctx, tracer_ctx, v_buff, data_args,
-				    direction, false, data_max_sz, false, 0);
+				    direction, false, data_max_sz, false, 0, 0);
 #endif
 }
 

agent/src/ebpf/kernel/include/socket_trace.h

@@ -219,6 +219,8 @@ struct tail_calls_context {
 	struct process_data_extra extra;
 	__u32 bytes_count;
 	struct member_fields_offset *offset;
+	__u32 bytes_remaining; // remaining bytes to output for this syscall
+	__u32 sent_bytes;       // bytes already output for this syscall
 };
 
 struct ctx_info_s {