Resolver implementation based on information /proc/net/(tcp[6]|udp)

bpf/events.c

@@ -17,9 +17,6 @@ void BPF_KPROBE(tcp_connect) {
 
     long err;
     __u64 cgroup_id = compat_get_current_cgroup_id(NULL);
-    if (!should_target_cgroup(cgroup_id)) {
-        return;
-    }
     __u64 id = tracer_get_current_pid_tgid();
 
     struct sock* sk = (struct sock*)PT_REGS_PARM1(ctx);
@@ -49,6 +46,9 @@ void BPF_KPROBE(tcp_connect) {
         return;
     }
 
+    __u64 key = (__u64)sk;
+    bpf_map_update_elem(&tcp_connect_context, &key, &ev.pid, BPF_ANY);
+
     bpf_probe_read_kernel_str(&ev.comm, 16, task->comm);
 
     ev.port_dst = bpf_ntohs(ev.port_dst);
@@ -99,6 +99,9 @@ void BPF_KRETPROBE(syscall__accept4_ret) {
         return;
     }
 
+    __u64 key = (__u64)sk;
+    bpf_map_update_elem(&tcp_accept_context, &key, &ev.pid, BPF_ANY);
+
     bpf_probe_read_kernel_str(&ev.comm, 16, task->comm);
 
     ev.port_src = bpf_ntohs(ev.port_src);
@@ -113,9 +116,6 @@ void BPF_KRETPROBE(do_accept) {
         return;
 
     __u64 cgroup_id = compat_get_current_cgroup_id(NULL);
-    if (!should_target_cgroup(cgroup_id)) {
-        return;
-    }
     struct file* f = (struct file*)PT_REGS_RC(ctx);
     if (!f)
         return;
@@ -141,6 +141,61 @@ int trace_cgroup_connect4(struct bpf_sock_addr* ctx) {
     return 1;
 }
 
+SEC("kprobe/tcp_close")
+void BPF_KPROBE(tcp_close) {
+    if (capture_disabled())
+        return;
+
+    long err;
+    __u64 cgroup_id = compat_get_current_cgroup_id(NULL);
+    __u64 id = tracer_get_current_pid_tgid();
+
+    struct sock* sk = (struct sock*)PT_REGS_PARM1(ctx);
+
+    short unsigned int family;
+    err = bpf_probe_read(&family, sizeof(family), (void*)&sk->__sk_common.skc_family);
+    if (err != 0) {
+        log_error(ctx, LOG_ERROR_READING_SOCKET_FAMILY, id, err, 0l);
+        return;
+    }
+
+    if (family != AF_INET) {
+        return;
+    }
+
+    __u16 event = 0;
+
+    __u64 key = (__u64)sk;
+    if (bpf_map_lookup_elem(&tcp_accept_context, &key)) {
+        event = SYSCALL_EVENT_ID_CLOSE_ACCEPT;
+        bpf_map_delete_elem(&tcp_accept_context, &key);
+    } else if (bpf_map_lookup_elem(&tcp_connect_context, &key)) {
+        event = SYSCALL_EVENT_ID_CLOSE_CONNECT;
+        bpf_map_delete_elem(&tcp_connect_context, &key);
+    } else {
+        return;
+    }
+
+    struct task_struct* task = (struct task_struct*)bpf_get_current_task();
+    struct syscall_event ev = {
+        .event_id = event,
+        .cgroup_id = cgroup_id,
+        .pid = get_task_pid(task),
+        .parent_pid = get_task_pid(get_parent_task(task)),
+        .host_pid = BPF_CORE_READ(task, tgid),
+        .host_parent_pid = get_parent_task_pid(task),
+    };
+
+    if (read_addrs_ports(ctx, (struct sock*)PT_REGS_PARM1(ctx), &ev.ip_src, &ev.port_src, &ev.ip_dst, &ev.port_dst)) {
+        return;
+    }
+
+    bpf_probe_read_kernel_str(&ev.comm, 16, task->comm);
+
+    ev.port_dst = bpf_ntohs(ev.port_dst);
+    bpf_perf_event_output(ctx, &syscall_events, BPF_F_CURRENT_CPU, &ev, sizeof(struct syscall_event));
+}
+
 static __always_inline int read_addrs_ports(struct pt_regs* ctx, struct sock* sk, __be32* saddr, __be16* sport, __be32* daddr, __be16* dport) {
     long err;
     __u64 id = tracer_get_current_pid_tgid();

bpf/include/events.h

@@ -20,6 +20,8 @@ BPF_LRU_HASH(accept_context, __u64, struct accept_data);
 
 #define SYSCALL_EVENT_ID_CONNECT 0
 #define SYSCALL_EVENT_ID_ACCEPT 1
+#define SYSCALL_EVENT_ID_CLOSE_CONNECT 2
+#define SYSCALL_EVENT_ID_CLOSE_ACCEPT 3
 
 struct syscall_event {
     char comm[16];

bpf/include/maps.h

@@ -191,4 +191,7 @@ BPF_LRU_HASH(go_kernel_read_context, __u64, __u32);
 BPF_LRU_HASH(go_user_kernel_write_context, __u64, struct address_info);
 BPF_LRU_HASH(go_user_kernel_read_context, __u64, struct address_info);
 
+BPF_LRU_HASH(tcp_connect_context, __u64, __u32);
+BPF_LRU_HASH(tcp_accept_context, __u64, __u32);
+
 #endif /* __MAPS__ */

go.mod

@@ -17,14 +17,17 @@ require (
 	github.com/hashicorp/golang-lru v0.5.4
 	github.com/hashicorp/golang-lru/v2 v2.0.2
 	github.com/knightsc/gapstone v0.0.0-20191231144527-6fa5afaf11a9
+	github.com/kubeshark/api v1.1.31
 	github.com/kubeshark/gopacket v1.1.30
 	github.com/kubeshark/tracerproto v1.0.3-0.20240730073449-de3a99a3719c
 	github.com/kubeshark/utils v0.0.0-20240912210808-416dca610f11
 	github.com/moby/moby v25.0.4+incompatible
 	github.com/moby/sys/mount v0.3.4
 	github.com/moby/sys/mountinfo v0.7.2
+	github.com/prometheus/procfs v0.15.1
 	github.com/rs/zerolog v1.32.0
 	github.com/vishvananda/netlink v1.2.1-beta.2
+	github.com/vishvananda/netns v0.0.0-20210104183010-2eb08e3e575f
 	golang.org/x/exp v0.0.0-20231219180239-dc181d75b848
 	golang.org/x/sys v0.20.0
 	k8s.io/api v0.28.3
@@ -74,12 +77,10 @@ require (
 	github.com/sirupsen/logrus v1.9.3 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.2.12 // indirect
-	github.com/vishvananda/netns v0.0.0-20210104183010-2eb08e3e575f // indirect
 	golang.org/x/arch v0.8.0 // indirect
 	golang.org/x/crypto v0.23.0 // indirect
 	golang.org/x/net v0.25.0 // indirect
 	golang.org/x/oauth2 v0.10.0 // indirect
-	golang.org/x/sync v0.5.0 // indirect
 	golang.org/x/term v0.20.0 // indirect
 	golang.org/x/text v0.15.0 // indirect
 	golang.org/x/time v0.3.0 // indirect

go.sum

@@ -122,6 +122,8 @@ github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/kubeshark/api v1.1.31 h1:stOsatiJ8C3SKLIStAwykc/dybHlyy9fYyH8b9tIv1c=
+github.com/kubeshark/api v1.1.31/go.mod h1:+Ua35OiwreWiUYfqJz0Aswn3UmsLctLUQh3tvxagQz4=
 github.com/kubeshark/gopacket v1.1.30 h1:Dz6eo7b6+NdVCrgiyKxlGEVTm0L6PwgbVvSomsuwIyU=
 github.com/kubeshark/gopacket v1.1.30/go.mod h1:Qo8/i/tdT74CCT7/pjO0L55Pktv5dQfj7M/Arv8MKm8=
 github.com/kubeshark/tracerproto v1.0.0/go.mod h1:+efDYkwXxwakmHRpxHVEekyXNtg/aFx0uSo/I0lGV9k=
@@ -172,6 +174,8 @@ github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/prometheus/procfs v0.15.1 h1:YagwOFzUgYfKKHX6Dr+sHT7km/hxC76UB0learggepc=
+github.com/prometheus/procfs v0.15.1/go.mod h1:fB45yRUv8NstnjriLhBQLuOUt+WW4BsoGhij/e3PBqk=
 github.com/rogpeppe/go-internal v1.6.1/go.mod h1:xXDCJY+GAPziupqXw64V24skbSoqbTEfhy4qGm1nDQc=
 github.com/rogpeppe/go-internal v1.8.0/go.mod h1:WmiCO8CzOY8rg0OYDC4/i/2WRWAB6poM+XZ2dLUbcbE=
 github.com/rogpeppe/go-internal v1.11.0 h1:cWPaGQEPrBb5/AsnsZesgZZ9yb1OQ+GOISoDNXVBh4M=
@@ -237,8 +241,8 @@ golang.org/x/oauth2 v0.10.0/go.mod h1:kTpgurOux7LqtuxjuyZa4Gj2gdezIt/jQtGnNFfypQ
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.5.0 h1:60k92dhOjHxJkrqnwsfl8KuaHbn/5dl0lUPUklKo3qE=
-golang.org/x/sync v0.5.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
+golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190606203320-7fc4e5ec1444/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

main.go

@@ -101,8 +101,6 @@ func main() {
 		}
 	}()
 
-	misc.InitDataDir()
-
 	run()
 }
 
@@ -143,6 +141,7 @@ func run() {
 	if clusterMode {
 		misc.SetDataDir(fmt.Sprintf("/app/data/%s", nodeName))
 	}
+	misc.InitDataDir()
 
 	err = createTracer()
 	if err != nil {

pkg/cgroup/cgroup_finder.go

@@ -25,7 +25,7 @@ var (
 )
 
 // Borrowed from https://github.com/aquasecurity/tracee/blob/main/pkg/containers/containers.go
-func getContainerIdByCgroupPath(cgroupPath string) (id string, runtime RuntimeId) {
+func GetContainerIdByCgroupPath(cgroupPath string) (id string, runtime RuntimeId) {
 	cgroupParts := strings.Split(cgroupPath, "/")
 
 	for i := len(cgroupParts) - 1; i >= 0; i = i - 1 {

pkg/cgroup/controller.go

@@ -29,7 +29,7 @@ type CgroupInfo struct {
 type CgroupsController interface {
 	EbpfCapturePossible() bool
 	AddCgroupPath(cgroupPath string) (cgroupID uint64, containerID string, ok bool)
-	PopulateSocketsInodes(inodeMap *ebpf.Map) error
+	PopulateSocketsInodes(isCgroupV2 bool, inodeMap *ebpf.Map) error
 	DelCgroupID(cgroupID uint64)
 	GetContainerID(cgroupID uint64) (containerID string)
 	GetCgroupsV2(containerId string) []CgroupInfo
@@ -58,7 +58,7 @@ func (e *CgroupsControllerImpl) EbpfCapturePossible() bool {
 func (e *CgroupsControllerImpl) AddCgroupPath(cgroupPath string) (cgroupID uint64, containerID string, ok bool) {
 	var err error
 
-	containerID, _ = getContainerIdByCgroupPath(cgroupPath)
+	containerID, _ = GetContainerIdByCgroupPath(cgroupPath)
 	if containerID == "" {
 		log.Debug().Str("path", cgroupPath).Msg("Can not get container id")
 		return
@@ -123,7 +123,7 @@ func (e *CgroupsControllerImpl) GetCgroupsV2(containerID string) (info []CgroupI
 }
 
 func (e *CgroupsControllerImpl) GetExistingCgroupsByCgroupPath(cgroupPath string) (info []CgroupInfo) {
-	containerID, _ := getContainerIdByCgroupPath(cgroupPath)
+	containerID, _ := GetContainerIdByCgroupPath(cgroupPath)
 	if containerID == "" {
 		return
 	}
@@ -136,7 +136,7 @@ func (e *CgroupsControllerImpl) GetCgroupV2MountPoint() string {
 	return e.cgroup.mountpoint
 }
 
-func (e *CgroupsControllerImpl) PopulateSocketsInodes(inodeMap *ebpf.Map) error {
+func (e *CgroupsControllerImpl) PopulateSocketsInodes(isCgroupV2 bool, inodeMap *ebpf.Map) error {
 	getContId := func(pid string) string {
 		path := filepath.Join(e.procfs, pid, "cgroup")
 		file, err := os.Open(path)
@@ -148,22 +148,22 @@ func (e *CgroupsControllerImpl) PopulateSocketsInodes(inodeMap *ebpf.Map) error
 		scanner := bufio.NewScanner(file)
 		for scanner.Scan() {
 			line := scanner.Text()
-			if !strings.Contains(line, ":cpuset:") {
+			if !isCgroupV2 && !strings.Contains(line, ":cpuset:") {
 				continue
 			}
 			items := strings.Split(line, ":")
 			cgroupPath := items[len(items)-1]
-			containerID, _ := getContainerIdByCgroupPath(cgroupPath)
+			containerID, _ := GetContainerIdByCgroupPath(cgroupPath)
 			return containerID
 		}
 
 		return ""
 	}
 
-	extractInode := func(socketId string, cgroups []CgroupInfo) {
+	extractInode := func(isCgroupsV2 bool, socketId string, cgroups []CgroupInfo) {
 		if inode, err := strconv.ParseUint(socketId, 10, 64); err == nil {
 			for _, cgroup := range cgroups {
-				if !strings.Contains(cgroup.CgroupPath, "/sys/fs/cgroup/cpuset") {
+				if !isCgroupsV2 && !strings.Contains(cgroup.CgroupPath, "/sys/fs/cgroup/cpuset") {
 					continue
 				}
 				if err := inodeMap.Update(inode, cgroup.CgroupID, ebpf.UpdateNoExist); err != nil {
@@ -174,7 +174,8 @@ func (e *CgroupsControllerImpl) PopulateSocketsInodes(inodeMap *ebpf.Map) error
 							log.Error().Err(err).Str("Cgroup Path", cgroup.CgroupPath).Uint64("Cgroup ID", cgroup.CgroupID).Uint64("inode", inode).Msg("Lookup inodemap failed")
 						}
 						if cgroup.CgroupID != cgroupExist {
-							log.Error().Err(err).Str("Cgroup Path", cgroup.CgroupPath).Uint64("Cgroup ID", cgroup.CgroupID).Uint64("inode", inode).Uint64("Cgroup ID exists", cgroupExist).Msg("Update inodemap failed")
+							// having one of IDs in inodemap must be enough
+							log.Debug().Err(err).Str("Cgroup Path", cgroup.CgroupPath).Uint64("Cgroup ID", cgroup.CgroupID).Uint64("inode", inode).Uint64("Cgroup ID exists", cgroupExist).Msg("Update inodemap failed")
 						}
 					}
 				} else {
@@ -184,7 +185,7 @@ func (e *CgroupsControllerImpl) PopulateSocketsInodes(inodeMap *ebpf.Map) error
 		}
 	}
 
-	findProcessSockets := func(prefix string, files []os.DirEntry, cgroups []CgroupInfo) {
+	findProcessSockets := func(isCgroupsV2 bool, prefix string, files []os.DirEntry, cgroups []CgroupInfo) {
 		for _, file := range files {
 			link, err := os.Readlink(filepath.Join(prefix, file.Name()))
 			if err != nil {
@@ -193,7 +194,7 @@ func (e *CgroupsControllerImpl) PopulateSocketsInodes(inodeMap *ebpf.Map) error
 			}
 			match := socketRegex.FindStringSubmatch(link)
 			if match != nil {
-				extractInode(match[1], cgroups)
+				extractInode(isCgroupsV2, match[1], cgroups)
 			}
 		}
 
@@ -230,7 +231,7 @@ func (e *CgroupsControllerImpl) PopulateSocketsInodes(inodeMap *ebpf.Map) error
 					continue
 				}
 
-				findProcessSockets(fdPath, files, cgroups)
+				findProcessSockets(isCgroupV2, fdPath, files, cgroups)
 			}
 		}
 	}

pkg/discoverer/discoverer.go

@@ -128,7 +128,7 @@ func (e *InternalEventsDiscovererImpl) scanExistingCgroups(isCgroupsV2 bool) {
 	_ = filepath.WalkDir("/sys/fs/cgroup", walk)
 
 	// scan all existing pids to find out all opened inodes of sockets
-	if err := e.cgroupsController.PopulateSocketsInodes(e.bpfObjects.BpfObjs.Inodemap); err != nil {
+	if err := e.cgroupsController.PopulateSocketsInodes(isCgroupsV2, e.bpfObjects.BpfObjs.Inodemap); err != nil {
 		log.Error().Err(err).Msg("Populate sockets inodes failed")
 	}
 }

pkg/hooks/syscall/tcp_kprobe_hooks.go

@@ -14,6 +14,7 @@ type tcpKprobeHooks struct {
 	accept      link.Link
 	acceptRet   link.Link
 	accept4     link.Link
+	tcpClose    link.Link
 }
 
 func (s *tcpKprobeHooks) installTcpKprobeHooks(bpfObjects *bpf.TracerObjects) error {
@@ -44,6 +45,11 @@ func (s *tcpKprobeHooks) installTcpKprobeHooks(bpfObjects *bpf.TracerObjects) er
 		log.Warn().Err(err).Msg("do_accept can not be attached. Probably system is running on incomatible kernel")
 	}
 
+	s.tcpClose, err = link.Kprobe("tcp_close", bpfObjects.TcpClose, nil)
+	if err != nil {
+		return errors.Wrap(err, 0)
+	}
+
 	return nil
 }
 
@@ -80,5 +86,11 @@ func (s *tcpKprobeHooks) close() []error {
 		}
 	}
 
+	if s.tcpClose != nil {
+		if err := s.tcpClose.Close(); err != nil {
+			returnValue = append(returnValue, err)
+		}
+	}
+
 	return returnValue
 }

pkg/poller/syscall/tracer_syscall_events.go

@@ -88,17 +88,18 @@ func (t *SyscallEventsTracer) pollEvents() {
 		var evName string
 		if ev.EventId == 0 {
 			evName = "connect"
-		}
-		if ev.EventId == 1 {
+		} else if ev.EventId == 1 {
 			evName = "accept"
+		} else if ev.EventId == 2 {
+			evName = "close connect"
+		} else if ev.EventId == 3 {
+			evName = "close accept"
 		}
 
 		var e events.SyscallEvent
 		e.SyscallEventMessage = ev
-		contID := t.cgroupController.GetContainerID(ev.CgroupID)
-		e.ContainerID = string(contID)
 
-		log.Debug().Msg(fmt.Sprintf("Syscall event %v: %v:%v->%v:%v command: %v host pid: %v host ppid: %v pid: %v ppid: %v cgroup id: %v container id: %v",
+		log.Debug().Msg(fmt.Sprintf("Syscall event %v: %v:%v->%v:%v command: %v host pid: %v host ppid: %v pid: %v ppid: %v cgroup id: %v",
 			evName,
 			toIP(e.IpSrc),
 			toPort(e.PortSrc),
@@ -110,7 +111,6 @@ func (t *SyscallEventsTracer) pollEvents() {
 			e.Pid,
 			e.ParentPid,
 			e.CgroupID,
-			e.ContainerID,
 		))
 
 		t.eventSocket.WriteObject(e)