Add support for tracking http2 client and server requests (#568)

.gitignore

@@ -70,3 +70,5 @@ test/integration/components/rubytestserver/testapi/tmp/storage/*
 test/integration/components/dotnetserver/obj/*
 test/oats/build/*
 test/cmd/grpc/client/grpclient
+test/integration/components/gohttp2/client/client
+test/integration/components/gohttp2/server/http2srv

Makefile

@@ -88,7 +88,7 @@ prereqs:
 	mkdir -p $(TEST_OUTPUT)/run
 	$(call go-install-tool,$(GOLANGCI_LINT),github.com/golangci/golangci-lint/cmd/golangci-lint@v1.54.2)
 	$(call go-install-tool,$(BPF2GO),github.com/cilium/ebpf/cmd/bpf2go@v0.10.0)
-	$(call go-install-tool,$(GO_OFFSETS_TRACKER),github.com/grafana/go-offsets-tracker/cmd/go-offsets-tracker@v0.1.6)
+	$(call go-install-tool,$(GO_OFFSETS_TRACKER),github.com/grafana/go-offsets-tracker/cmd/go-offsets-tracker@v0.1.7)
 	$(call go-install-tool,$(GOIMPORTS_REVISER),github.com/incu6us/goimports-reviser/v3@v3.4.5)
 	$(call go-install-tool,$(GO_LICENSES),github.com/google/go-licenses@v1.6.0)
 	$(call go-install-tool,$(KIND),sigs.k8s.io/kind@v0.20.0)

bpf/go_nethttp.c

@@ -97,9 +97,8 @@ int uprobe_readRequestReturns(struct pt_regs *ctx) {
     return 0;
 }
 
-SEC("uprobe/WriteHeader")
-int uprobe_WriteHeader(struct pt_regs *ctx) {
-    bpf_dbg_printk("=== uprobe/WriteHeader === ");
+static __always_inline int writeHeaderHelper(struct pt_regs *ctx, u64 req_offset) {
+        bpf_dbg_printk("=== uprobe/WriteHeader === ");
     void *goroutine_addr = GOROUTINE_PTR(ctx);
     bpf_dbg_printk("goroutine_addr %lx", goroutine_addr);
 
@@ -144,7 +143,7 @@ int uprobe_WriteHeader(struct pt_regs *ctx) {
 
     // Get request struct
     void *req_ptr = 0;
-    bpf_probe_read(&req_ptr, sizeof(req_ptr), (void *)(resp_ptr + resp_req_pos));
+    bpf_probe_read(&req_ptr, sizeof(req_ptr), (void *)(resp_ptr + req_offset));
 
     if (!req_ptr) {
         bpf_printk("can't find req inside the response value");
@@ -195,6 +194,11 @@ int uprobe_WriteHeader(struct pt_regs *ctx) {
     return 0;
 }
 
+SEC("uprobe/WriteHeader")
+int uprobe_WriteHeader(struct pt_regs *ctx) {
+    return writeHeaderHelper(ctx, resp_req_pos);
+}
+
 #ifndef NO_HEADER_PROPAGATION
 struct {
     __uint(type, BPF_MAP_TYPE_HASH);
@@ -378,4 +382,12 @@ SEC("uprobe/header_writeSubset")
 int uprobe_writeSubset(struct pt_regs *ctx) {
     return 0;
 }
-#endif
+#endif
+
+// HTTP 2.0 server support
+SEC("uprobe/http2ResponseWriterStateWriteHeader")
+int uprobe_http2ResponseWriterStateWriteHeader(struct pt_regs *ctx) {
+    bpf_dbg_printk("=== uprobe/proc http2 responseWriterState writeHeader === ");
+
+    return writeHeaderHelper(ctx, rws_req_pos);
+}

bpf/go_nethttp.h

@@ -29,5 +29,6 @@ volatile const u64 resp_req_pos;
 volatile const u64 req_header_ptr_pos;
 volatile const u64 io_writer_buf_ptr_pos;
 volatile const u64 io_writer_n_pos;
+volatile const u64 rws_req_pos;
 
 #endif

bpf/trace_common.h

@@ -252,7 +252,7 @@ static __always_inline void get_or_create_trace_info(http_connection_metadata_t
 #ifdef BPF_TRACEPARENT
     // The below buffer scan can be expensive on high volume of requests. We make it optional
     // for customers to enable it. Off by default.
-    if (!capture_header_buffer || !bpf_core_enum_value_exists(enum bpf_func_id, BPF_FUNC_loop)) {    
+    if (!capture_header_buffer) {
         bpf_map_update_elem(&trace_map, conn, tp_p, BPF_ANY);
         server_or_client_trace(meta, conn, tp_p);
         return;

configs/offsets/http2/inspect.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+
+	"golang.org/x/net/http2"
+)
+
+func checkErr(err error, msg string) {
+	if err == nil {
+		return
+	}
+	fmt.Printf("ERROR: %s: %s\n", msg, err)
+	os.Exit(1)
+}
+
+func main() {
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, "Hello, %v, http: %v\n", r.URL.Path, r.TLS == nil)
+	})
+
+	server := &http.Server{
+		Addr:    "0.0.0.0:8080",
+		Handler: handler,
+	}
+	http2.ConfigureServer(server, nil)
+
+	fmt.Printf("Listening [0.0.0.0:8080]...\n")
+	checkErr(server.ListenAndServeTLS("cert.pem", "key.pem"), "while listening")
+}

configs/offsets/tracker_input.json

@@ -34,9 +34,21 @@
       ],
       "vendor/golang.org/x/net/http2/hpack.Encoder": [
         "w"
-      ]          
+      ]
     }
   },
+  "golang.org/x/net": {
+    "inspect": "./configs/offsets/http2/inspect.go",
+    "versions": ">= 0.12.0",
+    "fields": {
+      "golang.org/x/net/http2.responseWriterState": [
+        "req"
+      ],
+      "golang.org/x/net/http2/hpack.Encoder": [
+        "w"
+      ]
+    }
+  },  
   "google.golang.org/grpc": {
     "versions": ">= 1.40",
     "fields": {