bpf: sockmap sample program

This program binds a program to a cgroup and then matches hard
coded IP addresses and adds these to a sockmap.

This will receive messages from the backend and send them to
the client.

     client:X <---> frontend:10000 client:X <---> backend:10001

To keep things simple this is only designed for 1:1 connections
using hard coded values. A more complete example would allow many
backends and clients.

To run,

 # sockmap <cgroup2_dir>

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 480 insertions, 2 deletions

diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index 899f40310bc3..a8552b8a2ab6 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -65,6 +65,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
 	bool is_cgroup_skb = strncmp(event, "cgroup/skb", 10) == 0;
 	bool is_cgroup_sk = strncmp(event, "cgroup/sock", 11) == 0;
 	bool is_sockops = strncmp(event, "sockops", 7) == 0;
+	bool is_sk_skb = strncmp(event, "sk_skb", 6) == 0;
 	size_t insns_cnt = size / sizeof(struct bpf_insn);
 	enum bpf_prog_type prog_type;
 	char buf[256];
@@ -92,6 +93,8 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
 		prog_type = BPF_PROG_TYPE_CGROUP_SOCK;
 	} else if (is_sockops) {
 		prog_type = BPF_PROG_TYPE_SOCK_OPS;
+	} else if (is_sk_skb) {
+		prog_type = BPF_PROG_TYPE_SK_SKB;
 	} else {
 		printf("Unknown event '%s'\n", event);
 		return -1;
@@ -109,7 +112,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
 	if (is_xdp || is_perf_event || is_cgroup_skb || is_cgroup_sk)
 		return 0;
 
-	if (is_socket || is_sockops) {
+	if (is_socket || is_sockops || is_sk_skb) {
 		if (is_socket)
 			event += 6;
 		else
@@ -567,7 +570,8 @@ static int do_load_bpf_file(const char *path, fixup_map_cb fixup_map)
 		    memcmp(shname, "perf_event", 10) == 0 ||
 		    memcmp(shname, "socket", 6) == 0 ||
 		    memcmp(shname, "cgroup/", 7) == 0 ||
-		    memcmp(shname, "sockops", 7) == 0) {
+		    memcmp(shname, "sockops", 7) == 0 ||
+		    memcmp(shname, "sk_skb", 6) == 0) {
 			ret = load_and_attach(shname, data->d_buf,
 					      data->d_size);
 			if (ret != 0)
diff --git a/samples/sockmap/Makefile b/samples/sockmap/Makefile
new file mode 100644
index 000000000000..9291ab8e0f8c
--- /dev/null
+++ b/samples/sockmap/Makefile
@@ -0,0 +1,78 @@
+# kbuild trick to avoid linker error. Can be omitted if a module is built.
+obj- := dummy.o
+
+# List of programs to build
+hostprogs-y := sockmap
+
+# Libbpf dependencies
+LIBBPF := ../../tools/lib/bpf/bpf.o
+
+HOSTCFLAGS += -I$(objtree)/usr/include
+HOSTCFLAGS += -I$(srctree)/tools/lib/
+HOSTCFLAGS += -I$(srctree)/tools/testing/selftests/bpf/
+HOSTCFLAGS += -I$(srctree)/tools/lib/ -I$(srctree)/tools/include
+HOSTCFLAGS += -I$(srctree)/tools/perf
+
+sockmap-objs := ../bpf/bpf_load.o $(LIBBPF) sockmap_user.o
+
+# Tell kbuild to always build the programs
+always := $(hostprogs-y)
+always += sockmap_kern.o
+
+HOSTLOADLIBES_sockmap += -lelf -lpthread
+
+# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
+#  make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
+LLC ?= llc
+CLANG ?= clang
+
+# Trick to allow make to be run from this directory
+all:
+	$(MAKE) -C ../../ $(CURDIR)/
+
+clean:
+	$(MAKE) -C ../../ M=$(CURDIR) clean
+	@rm -f *~
+
+$(obj)/syscall_nrs.s:	$(src)/syscall_nrs.c
+	$(call if_changed_dep,cc_s_c)
+
+$(obj)/syscall_nrs.h:	$(obj)/syscall_nrs.s FORCE
+	$(call filechk,offsets,__SYSCALL_NRS_H__)
+
+clean-files += syscall_nrs.h
+
+FORCE:
+
+
+# Verify LLVM compiler tools are available and bpf target is supported by llc
+.PHONY: verify_cmds verify_target_bpf $(CLANG) $(LLC)
+
+verify_cmds: $(CLANG) $(LLC)
+	@for TOOL in $^ ; do \
+		if ! (which -- "$${TOOL}" > /dev/null 2>&1); then \
+			echo "*** ERROR: Cannot find LLVM tool $${TOOL}" ;\
+			exit 1; \
+		else true; fi; \
+	done
+
+verify_target_bpf: verify_cmds
+	@if ! (${LLC} -march=bpf -mattr=help > /dev/null 2>&1); then \
+		echo "*** ERROR: LLVM (${LLC}) does not support 'bpf' target" ;\
+		echo "   NOTICE: LLVM version >= 3.7.1 required" ;\
+		exit 2; \
+	else true; fi
+
+$(src)/*.c: verify_target_bpf
+
+# asm/sysreg.h - inline assembly used by it is incompatible with llvm.
+# But, there is no easy way to fix it, so just exclude it since it is
+# useless for BPF samples.
+$(obj)/%.o: $(src)/%.c
+	$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) -I$(obj) \
+		-D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \
+		-Wno-compare-distinct-pointer-types \
+		-Wno-gnu-variable-sized-type-not-at-end \
+		-Wno-address-of-packed-member -Wno-tautological-compare \
+		-Wno-unknown-warning-option \
+		-O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@
diff --git a/samples/sockmap/sockmap_kern.c b/samples/sockmap/sockmap_kern.c
new file mode 100644
index 000000000000..6ff986f7059b
--- /dev/null
+++ b/samples/sockmap/sockmap_kern.c
@@ -0,0 +1,110 @@
+/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <uapi/linux/bpf.h>
+#include <uapi/linux/if_ether.h>
+#include <uapi/linux/if_packet.h>
+#include <uapi/linux/ip.h>
+#include "../../tools/testing/selftests/bpf/bpf_helpers.h"
+#include "../../tools/testing/selftests/bpf/bpf_endian.h"
+
+/* Sockmap sample program connects a client and a backend together
+ * using cgroups.
+ *
+ *    client:X <---> frontend:80 client:X <---> backend:80
+ *
+ * For simplicity we hard code values here and bind 1:1. The hard
+ * coded values are part of the setup in sockmap.sh script that
+ * is associated with this BPF program.
+ *
+ * The bpf_printk is verbose and prints information as connections
+ * are established and verdicts are decided.
+ */
+
+#define bpf_printk(fmt, ...)					\
+({								\
+	       char ____fmt[] = fmt;				\
+	       bpf_trace_printk(____fmt, sizeof(____fmt),	\
+				##__VA_ARGS__);			\
+})
+
+struct bpf_map_def SEC("maps") sock_map = {
+	.type = BPF_MAP_TYPE_SOCKMAP,
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.max_entries = 20,
+};
+
+SEC("sk_skb1")
+int bpf_prog1(struct __sk_buff *skb)
+{
+	return skb->len;
+}
+
+SEC("sk_skb2")
+int bpf_prog2(struct __sk_buff *skb)
+{
+	__u32 lport = skb->local_port;
+	__u32 rport = skb->remote_port;
+	int ret = 0;
+
+	if (lport == 10000)
+		ret = 10;
+	else
+		ret = 1;
+
+	bpf_printk("sockmap: %d -> %d @ %d\n", lport, bpf_ntohl(rport), ret);
+	return bpf_sk_redirect_map(&sock_map, ret, 0);
+}
+
+SEC("sockops")
+int bpf_sockmap(struct bpf_sock_ops *skops)
+{
+	__u32 lport, rport;
+	int op, err = 0, index, key, ret;
+
+
+	op = (int) skops->op;
+
+	switch (op) {
+	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
+		lport = skops->local_port;
+		rport = skops->remote_port;
+
+		if (lport == 10000) {
+			ret = 1;
+			err = bpf_sock_map_update(skops, &sock_map, &ret,
+						  BPF_NOEXIST,
+						  BPF_SOCKMAP_STRPARSER);
+			bpf_printk("passive(%i -> %i) map ctx update err: %d\n",
+				   lport, bpf_ntohl(rport), err);
+		}
+		break;
+	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
+		lport = skops->local_port;
+		rport = skops->remote_port;
+
+		if (bpf_ntohl(rport) == 10001) {
+			ret = 10;
+			err = bpf_sock_map_update(skops, &sock_map, &ret,
+						  BPF_NOEXIST,
+						  BPF_SOCKMAP_STRPARSER);
+			bpf_printk("active(%i -> %i) map ctx update err: %d\n",
+				   lport, bpf_ntohl(rport), err);
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+char _license[] SEC("license") = "GPL";
diff --git a/samples/sockmap/sockmap_user.c b/samples/sockmap/sockmap_user.c
new file mode 100644
index 000000000000..fb78f5abefb4
--- /dev/null
+++ b/samples/sockmap/sockmap_user.c
@@ -0,0 +1,286 @@
+/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <sys/select.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <stdbool.h>
+#include <signal.h>
+#include <fcntl.h>
+
+#include <sys/time.h>
+#include <sys/types.h>
+
+#include <linux/netlink.h>
+#include <linux/socket.h>
+#include <linux/sock_diag.h>
+#include <linux/bpf.h>
+#include <linux/if_link.h>
+#include <assert.h>
+#include <libgen.h>
+
+#include "../bpf/bpf_load.h"
+#include "../bpf/bpf_util.h"
+#include "../bpf/libbpf.h"
+
+int running;
+void running_handler(int a);
+
+/* randomly selected ports for testing on lo */
+#define S1_PORT 10000
+#define S2_PORT 10001
+
+static int sockmap_test_sockets(int rate, int dot)
+{
+	int i, sc, err, max_fd, one = 1;
+	int s1, s2, c1, c2, p1, p2;
+	struct sockaddr_in addr;
+	struct timeval timeout;
+	char buf[1024] = {0};
+	int *fds[4] = {&s1, &s2, &c1, &c2};
+	fd_set w;
+
+	s1 = s2 = p1 = p2 = c1 = c2 = 0;
+
+	/* Init sockets */
+	for (i = 0; i < 4; i++) {
+		*fds[i] = socket(AF_INET, SOCK_STREAM, 0);
+		if (*fds[i] < 0) {
+			perror("socket s1 failed()");
+			err = *fds[i];
+			goto out;
+		}
+	}
+
+	/* Allow reuse */
+	for (i = 0; i < 2; i++) {
+		err = setsockopt(*fds[i], SOL_SOCKET, SO_REUSEADDR,
+				 (char *)&one, sizeof(one));
+		if (err) {
+			perror("setsockopt failed()");
+			goto out;
+		}
+	}
+
+	/* Non-blocking sockets */
+	for (i = 0; i < 4; i++) {
+		err = ioctl(*fds[i], FIONBIO, (char *)&one);
+		if (err < 0) {
+			perror("ioctl s1 failed()");
+			goto out;
+		}
+	}
+
+	/* Bind server sockets */
+	memset(&addr, 0, sizeof(struct sockaddr_in));
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = inet_addr("127.0.0.1");
+
+	addr.sin_port = htons(S1_PORT);
+	err = bind(s1, (struct sockaddr *)&addr, sizeof(addr));
+	if (err < 0) {
+		perror("bind s1 failed()\n");
+		goto out;
+	}
+
+	addr.sin_port = htons(S2_PORT);
+	err = bind(s2, (struct sockaddr *)&addr, sizeof(addr));
+	if (err < 0) {
+		perror("bind s2 failed()\n");
+		goto out;
+	}
+
+	/* Listen server sockets */
+	addr.sin_port = htons(S1_PORT);
+	err = listen(s1, 32);
+	if (err < 0) {
+		perror("listen s1 failed()\n");
+		goto out;
+	}
+
+	addr.sin_port = htons(S2_PORT);
+	err = listen(s2, 32);
+	if (err < 0) {
+		perror("listen s1 failed()\n");
+		goto out;
+	}
+
+	/* Initiate Connect */
+	addr.sin_port = htons(S1_PORT);
+	err = connect(c1, (struct sockaddr *)&addr, sizeof(addr));
+	if (err < 0 && errno != EINPROGRESS) {
+		perror("connect c1 failed()\n");
+		goto out;
+	}
+
+	addr.sin_port = htons(S2_PORT);
+	err = connect(c2, (struct sockaddr *)&addr, sizeof(addr));
+	if (err < 0 && errno != EINPROGRESS) {
+		perror("connect c2 failed()\n");
+		goto out;
+	}
+
+	/* Accept Connecrtions */
+	p1 = accept(s1, NULL, NULL);
+	if (p1 < 0) {
+		perror("accept s1 failed()\n");
+		goto out;
+	}
+
+	p2 = accept(s2, NULL, NULL);
+	if (p2 < 0) {
+		perror("accept s1 failed()\n");
+		goto out;
+	}
+
+	max_fd = p2;
+	timeout.tv_sec = 10;
+	timeout.tv_usec = 0;
+
+	printf("connected sockets: c1 <-> p1, c2 <-> p2\n");
+	printf("cgroups binding: c1(%i) <-> s1(%i) - - - c2(%i) <-> s2(%i)\n",
+		c1, s1, c2, s2);
+
+	/* Ping/Pong data from client to server */
+	sc = send(c1, buf, sizeof(buf), 0);
+	if (sc < 0) {
+		perror("send failed()\n");
+		goto out;
+	}
+
+	do {
+		int s, rc, i;
+
+		/* FD sets */
+		FD_ZERO(&w);
+		FD_SET(c1, &w);
+		FD_SET(c2, &w);
+		FD_SET(p1, &w);
+		FD_SET(p2, &w);
+
+		s = select(max_fd + 1, &w, NULL, NULL, &timeout);
+		if (s == -1) {
+			perror("select()");
+			break;
+		} else if (!s) {
+			fprintf(stderr, "unexpected timeout\n");
+			break;
+		}
+
+		for (i = 0; i <= max_fd && s > 0; ++i) {
+			if (!FD_ISSET(i, &w))
+				continue;
+
+			s--;
+
+			rc = recv(i, buf, sizeof(buf), 0);
+			if (rc < 0) {
+				if (errno != EWOULDBLOCK) {
+					perror("recv failed()\n");
+					break;
+				}
+			}
+
+			if (rc == 0) {
+				close(i);
+				break;
+			}
+
+			sc = send(i, buf, rc, 0);
+			if (sc < 0) {
+				perror("send failed()\n");
+				break;
+			}
+		}
+		sleep(rate);
+		if (dot) {
+			printf(".");
+			fflush(stdout);
+
+		}
+	} while (running);
+
+out:
+	close(s1);
+	close(s2);
+	close(p1);
+	close(p2);
+	close(c1);
+	close(c2);
+	return err;
+}
+
+int main(int argc, char **argv)
+{
+	int rate = 1, dot = 1;
+	char filename[256];
+	int err, cg_fd;
+	char *cg_path;
+
+	cg_path = argv[argc - 1];
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+	running = 1;
+
+	/* catch SIGINT */
+	signal(SIGINT, running_handler);
+
+	if (load_bpf_file(filename)) {
+		fprintf(stderr, "load_bpf_file: (%s) %s\n",
+			filename, strerror(errno));
+		return 1;
+	}
+
+	/* Cgroup configuration */
+	cg_fd = open(cg_path, O_DIRECTORY, O_RDONLY);
+	if (cg_fd < 0) {
+		fprintf(stderr, "ERROR: (%i) open cg path failed: %s\n",
+			cg_fd, cg_path);
+		return cg_fd;
+	}
+
+	/* Attach programs to sockmap */
+	err = __bpf_prog_attach(prog_fd[0], prog_fd[1], map_fd[0],
+				BPF_CGROUP_SMAP_INGRESS, 0);
+	if (err) {
+		fprintf(stderr, "ERROR: bpf_prog_attach (sockmap): %d (%s)\n",
+			err, strerror(errno));
+		return err;
+	}
+
+	/* Attach to cgroups */
+	err = bpf_prog_attach(prog_fd[2], cg_fd, BPF_CGROUP_SOCK_OPS, 0);
+	if (err) {
+		fprintf(stderr, "ERROR: bpf_prog_attach (groups): %d (%s)\n",
+			err, strerror(errno));
+		return err;
+	}
+
+	err = sockmap_test_sockets(rate, dot);
+	if (err) {
+		fprintf(stderr, "ERROR: test socket failed: %d\n", err);
+		return err;
+	}
+	return 0;
+}
+
+void running_handler(int a)
+{
+	running = 0;
+}