Add skb_adjust_room() for SK_SKB

.travis.yml

@@ -0,0 +1,33 @@
+sudo: required
+language: bash
+dist: bionic
+services:
+    - docker
+
+env:
+    global:
+        - PROJECT_NAME='libbpf'
+        - AUTHOR_EMAIL="$(git log -1 --pretty=\"%aE\")"
+        - REPO_ROOT="$TRAVIS_BUILD_DIR"
+        - CI_ROOT="$REPO_ROOT/travis-ci"
+        - VMTEST_ROOT="$CI_ROOT/vmtest"
+
+addons:
+    apt:
+        packages:
+            - qemu-kvm
+            - zstd
+            - binutils-dev
+            - elfutils
+            - libcap-dev
+            - libelf-dev
+            - libdw-dev
+            - python3-docutils
+
+jobs:
+    include:
+        - stage: Builds & Tests
+          name: Kernel LATEST + selftests
+          language: bash
+          env: KERNEL=LATEST
+          script:  $CI_ROOT/vmtest/run_vmtest.sh || travis_terminate 1

net/core/filter.c

@@ -76,6 +76,7 @@
 #include <net/bpf_sk_storage.h>
 #include <net/transp_v6.h>
 #include <linux/btf_ids.h>
+#include <net/tls.h>
 
 static const struct bpf_func_proto *
 bpf_sk_base_func_proto(enum bpf_func_id func_id);
@@ -3479,6 +3480,48 @@ static u32 __bpf_skb_max_len(const struct sk_buff *skb)
 			  SKB_MAX_ALLOC;
 }
 
+BPF_CALL_4(sk_skb_adjust_room, struct sk_buff *, skb, s32, len_diff,
+	   u32, mode, u64, flags)
+{
+	u32 len_diff_abs = abs(len_diff);
+	bool shrink = len_diff < 0;
+	int ret = 0;
+
+	if (unlikely(flags || mode))
+		return -EINVAL;
+	if (unlikely(len_diff_abs > 0xfffU))
+		return -EFAULT;
+
+	if (!shrink) {
+		ret = skb_cow(skb, len_diff);
+		if (unlikely(ret < 0))
+			return ret;
+		__skb_push(skb, len_diff_abs);
+		memset(skb->data, 0, len_diff_abs);
+	} else {
+		if (unlikely(!pskb_may_pull(skb, len_diff_abs)))
+			return -ENOMEM;
+		__skb_pull(skb, len_diff_abs);
+	}
+	bpf_compute_data_end_sk_skb(skb);
+	if (tls_sw_has_ctx_rx(skb->sk)) {
+		struct strp_msg *rxm = strp_msg(skb);
+
+		rxm->full_len += len_diff;
+	}
+	return ret;
+}
+
+static const struct bpf_func_proto sk_skb_adjust_room_proto = {
+	.func		= sk_skb_adjust_room,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_ANYTHING,
+};
+
 BPF_CALL_4(bpf_skb_adjust_room, struct sk_buff *, skb, s32, len_diff,
 	   u32, mode, u64, flags)
 {
@@ -6745,6 +6788,7 @@ bool bpf_helper_changes_pkt_data(void *func)
 	    func == bpf_skb_change_tail ||
 	    func == sk_skb_change_tail ||
 	    func == bpf_skb_adjust_room ||
+	    func == sk_skb_adjust_room ||
 	    func == bpf_skb_pull_data ||
 	    func == sk_skb_pull_data ||
 	    func == bpf_clone_redirect ||
@@ -7218,6 +7262,8 @@ sk_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &sk_skb_change_tail_proto;
 	case BPF_FUNC_skb_change_head:
 		return &sk_skb_change_head_proto;
+	case BPF_FUNC_skb_adjust_room:
+		return &sk_skb_adjust_room_proto;
 	case BPF_FUNC_get_socket_cookie:
 		return &bpf_get_socket_cookie_proto;
 	case BPF_FUNC_get_socket_uid:

tools/testing/selftests/bpf/progs/test_sockmap_kern.h

@@ -131,39 +131,55 @@ int bpf_prog2(struct __sk_buff *skb)
 
 }
 
-SEC("sk_skb3")
-int bpf_prog3(struct __sk_buff *skb)
+static inline void bpf_write_pass(struct __sk_buff *skb, int offset)
 {
-	const int one = 1;
-	int err, *f, ret = SK_PASS;
+	int err = bpf_skb_pull_data(skb, 6 + offset);
 	void *data_end;
 	char *c;
 
-	err = bpf_skb_pull_data(skb, 19);
 	if (err)
-		goto tls_out;
+		return;
 
 	c = (char *)(long)skb->data;
 	data_end = (void *)(long)skb->data_end;
 
-	if (c + 18 < data_end)
-		memcpy(&c[13], "PASS", 4);
+	if (c + 5 + offset < data_end)
+		memcpy(c + offset, "PASS", 4);
+}
+
+SEC("sk_skb3")
+int bpf_prog3(struct __sk_buff *skb)
+{
+	int err, *f, ret = SK_PASS;
+	const int one = 1;
+
 	f = bpf_map_lookup_elem(&sock_skb_opts, &one);
 	if (f && *f) {
 		__u64 flags = 0;
 
 		ret = 0;
 		flags = *f;
+
+		err = bpf_skb_adjust_room(skb, -13, 0, 0);
+		if (err)
+			return SK_DROP;
+		err = bpf_skb_adjust_room(skb, 4, 0, 0);
+		if (err)
+			return SK_DROP;
+		bpf_write_pass(skb, 0);
 #ifdef SOCKMAP
 		return bpf_sk_redirect_map(skb, &tls_sock_map, ret, flags);
 #else
 		return bpf_sk_redirect_hash(skb, &tls_sock_map, &ret, flags);
 #endif
 	}
-
 	f = bpf_map_lookup_elem(&sock_skb_opts, &one);
 	if (f && *f)
 		ret = SK_DROP;
+	err = bpf_skb_adjust_room(skb, 4, 0, 0);
+	if (err)
+		return SK_DROP;
+	bpf_write_pass(skb, 13);
 tls_out:
 	return ret;
 }

tools/testing/selftests/bpf/test_sockmap.c

@@ -518,28 +518,13 @@ static int msg_verify_data(struct msghdr *msg, int size, int chunk_sz)
 		if (i == 0 && txmsg_ktls_skb) {
 			if (msg->msg_iov[i].iov_len < 4)
 				return -EIO;
-			if (txmsg_ktls_skb_redir) {
-				if (memcmp(&d[13], "PASS", 4) != 0) {
-					fprintf(stderr,
-						"detected redirect ktls_skb data error with skb ingress update @iov[%i]:%i \"%02x %02x %02x %02x\" != \"PASS\"\n", i, 0, d[13], d[14], d[15], d[16]);
-					return -EIO;
-				}
-				d[13] = 0;
-				d[14] = 1;
-				d[15] = 2;
-				d[16] = 3;
-				j = 13;
-			} else if (txmsg_ktls_skb) {
-				if (memcmp(d, "PASS", 4) != 0) {
-					fprintf(stderr,
-						"detected ktls_skb data error with skb ingress update @iov[%i]:%i \"%02x %02x %02x %02x\" != \"PASS\"\n", i, 0, d[0], d[1], d[2], d[3]);
-					return -EIO;
-				}
-				d[0] = 0;
-				d[1] = 1;
-				d[2] = 2;
-				d[3] = 3;
+			if (memcmp(d, "PASS", 4) != 0) {
+				fprintf(stderr,
+					"detected skb data error with skb ingress update @iov[%i]:%i \"%02x %02x %02x %02x\" != \"PASS\"\n",
+					i, 0, d[0], d[1], d[2], d[3]);
+				return -EIO;
 			}
+			j = 4; /* advance index past PASS header */
 		}
 
 		for (; j < msg->msg_iov[i].iov_len && size; j++) {

travis-ci/managers/debian.sh

@@ -0,0 +1,84 @@
+#!/bin/bash
+
+PHASES=(${@:-SETUP RUN RUN_ASAN CLEANUP})
+DEBIAN_RELEASE="${DEBIAN_RELEASE:-testing}"
+CONT_NAME="${CONT_NAME:-libbpf-debian-$DEBIAN_RELEASE}"
+ENV_VARS="${ENV_VARS:-}"
+DOCKER_RUN="${DOCKER_RUN:-docker run}"
+REPO_ROOT="${REPO_ROOT:-$PWD}"
+ADDITIONAL_DEPS=(clang pkg-config gcc-8)
+CFLAGS="-g -O2 -Werror -Wall"
+
+function info() {
+    echo -e "\033[33;1m$1\033[0m"
+}
+
+function error() {
+    echo -e "\033[31;1m$1\033[0m"
+}
+
+function docker_exec() {
+    docker exec $ENV_VARS -it $CONT_NAME "$@"
+}
+
+set -e
+
+source "$(dirname $0)/travis_wait.bash"
+
+for phase in "${PHASES[@]}"; do
+    case $phase in
+        SETUP)
+            info "Setup phase"
+            info "Using Debian $DEBIAN_RELEASE"
+
+            sudo apt-get -y -o Dpkg::Options::="--force-confnew" install docker-ce
+            docker --version
+
+            docker pull debian:$DEBIAN_RELEASE
+            info "Starting container $CONT_NAME"
+            $DOCKER_RUN -v $REPO_ROOT:/build:rw \
+                        -w /build --privileged=true --name $CONT_NAME \
+                        -dit --net=host debian:$DEBIAN_RELEASE /bin/bash
+            docker_exec bash -c "echo deb-src http://deb.debian.org/debian $DEBIAN_RELEASE main >>/etc/apt/sources.list"
+            docker_exec apt-get -y update
+            docker_exec apt-get -y build-dep libelf-dev
+            docker_exec apt-get -y install libelf-dev
+            docker_exec apt-get -y install "${ADDITIONAL_DEPS[@]}"
+            ;;
+        RUN|RUN_CLANG|RUN_GCC8|RUN_ASAN|RUN_CLANG_ASAN|RUN_GCC8_ASAN)
+            if [[ "$phase" = *"CLANG"* ]]; then
+                ENV_VARS="-e CC=clang -e CXX=clang++"
+                CC="clang"
+            elif [[ "$phase" = *"GCC8"* ]]; then
+                ENV_VARS="-e CC=gcc-8 -e CXX=g++-8"
+                CC="gcc-8"
+            else
+                CFLAGS="${CFLAGS} -Wno-stringop-truncation"
+            fi
+            if [[ "$phase" = *"ASAN"* ]]; then
+                CFLAGS="${CFLAGS} -fsanitize=address,undefined"
+            fi
+            docker_exec mkdir build install
+            docker_exec ${CC:-cc} --version
+            info "build"
+	    docker_exec make -j$((4*$(nproc))) CFLAGS="${CFLAGS}" -C ./src -B OBJDIR=../build
+            info "ldd build/libbpf.so:"
+            docker_exec ldd build/libbpf.so
+            if ! docker_exec ldd build/libbpf.so | grep -q libelf; then
+                error "No reference to libelf.so in libbpf.so!"
+                exit 1
+            fi
+            info "install"
+            docker_exec make -j$((4*$(nproc))) -C src OBJDIR=../build DESTDIR=../install install
+            docker_exec rm -rf build install
+            ;;
+        CLEANUP)
+            info "Cleanup phase"
+            docker stop $CONT_NAME
+            docker rm -f $CONT_NAME
+            ;;
+        *)
+            echo >&2 "Unknown phase '$phase'"
+            exit 1
+    esac
+done

travis-ci/managers/travis_wait.bash

@@ -0,0 +1,61 @@
+# This was borrowed from https://github.com/travis-ci/travis-build/tree/master/lib/travis/build/bash
+# to get around https://github.com/travis-ci/travis-ci/issues/9979. It should probably be removed
+# as soon as Travis CI has started to provide an easy way to export the functions to bash scripts.
+
+travis_jigger() {
+  local cmd_pid="${1}"
+  shift
+  local timeout="${1}"
+  shift
+  local count=0
+
+  echo -e "\\n"
+
+  while [[ "${count}" -lt "${timeout}" ]]; do
+    count="$((count + 1))"
+    echo -ne "Still running (${count} of ${timeout}): ${*}\\r"
+    sleep 60
+  done
+
+  echo -e "\\n${ANSI_RED}Timeout (${timeout} minutes) reached. Terminating \"${*}\"${ANSI_RESET}\\n"
+  kill -9 "${cmd_pid}"
+}
+
+travis_wait() {
+  local timeout="${1}"
+
+  if [[ "${timeout}" =~ ^[0-9]+$ ]]; then
+    shift
+  else
+    timeout=20
+  fi
+
+  local cmd=("${@}")
+  local log_file="travis_wait_${$}.log"
+
+  "${cmd[@]}" &>"${log_file}" &
+  local cmd_pid="${!}"
+
+  travis_jigger "${!}" "${timeout}" "${cmd[@]}" &
+  local jigger_pid="${!}"
+  local result
+
+  {
+    set +e
+    wait "${cmd_pid}" 2>/dev/null
+    result="${?}"
+    ps -p"${jigger_pid}" &>/dev/null && kill "${jigger_pid}"
+    set -e
+  }
+
+  if [[ "${result}" -eq 0 ]]; then
+    echo -e "\\n${ANSI_GREEN}The command ${cmd[*]} exited with ${result}.${ANSI_RESET}"
+  else
+    echo -e "\\n${ANSI_RED}The command ${cmd[*]} exited with ${result}.${ANSI_RESET}"
+  fi
+
+  echo -e "\\n${ANSI_GREEN}Log:${ANSI_RESET}\\n"
+  cat "${log_file}"
+
+  return "${result}"
+}

travis-ci/managers/ubuntu.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+set -e
+set -x
+
+RELEASE="bionic"
+
+echo "deb-src http://archive.ubuntu.com/ubuntu/ $RELEASE main restricted universe multiverse" >>/etc/apt/sources.list
+
+apt-get update
+apt-get -y build-dep libelf-dev
+apt-get install -y libelf-dev pkg-config
+
+source "$(dirname $0)/travis_wait.bash"
+
+cd $REPO_ROOT
+
+CFLAGS="-g -O2 -Werror -Wall -fsanitize=address,undefined"
+mkdir build install
+cc --version
+make -j$((4*$(nproc))) CFLAGS="${CFLAGS}" -C ./src -B OBJDIR=../build
+ldd build/libbpf.so
+if ! ldd build/libbpf.so | grep -q libelf; then
+    echo "FAIL: No reference to libelf.so in libbpf.so!"
+    exit 1
+fi
+make -j$((4*$(nproc))) -C src OBJDIR=../build DESTDIR=../install install
+rm -rf build install