Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
The following pull-request contains BPF updates for your *net-next* tree.

There is a small merge conflict in libbpf (Cc Andrii so he's in the loop
as well):

        for (i = 1; i <= btf__get_nr_types(btf); i++) {
                t = (struct btf_type *)btf__type_by_id(btf, i);

                if (!has_datasec && btf_is_var(t)) {
                        /* replace VAR with INT */
                        t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
  <<<<<<< HEAD
                        /*
                         * using size = 1 is the safest choice, 4 will be too
                         * big and cause kernel BTF validation failure if
                         * original variable took less than 4 bytes
                         */
                        t->size = 1;
                        *(int *)(t+1) = BTF_INT_ENC(0, 0, 8);
                } else if (!has_datasec && kind == BTF_KIND_DATASEC) {
  =======
                        t->size = sizeof(int);
                        *(int *)(t + 1) = BTF_INT_ENC(0, 0, 32);
                } else if (!has_datasec && btf_is_datasec(t)) {
  >>>>>>> 72ef80b5ee131e96172f19e74b4f98fa3404efe8
                        /* replace DATASEC with STRUCT */

Conflict is between the two commits 1d4126c4e119 ("libbpf: sanitize VAR to
conservative 1-byte INT") and b03bc6853c0e ("libbpf: convert libbpf code to
use new btf helpers"), so we need to pick the sanitation fixup as well as
use the new btf_is_datasec() helper and the whitespace cleanup. Looks like
the following:

  [...]
                if (!has_datasec && btf_is_var(t)) {
                        /* replace VAR with INT */
                        t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
                        /*
                         * using size = 1 is the safest choice, 4 will be too
                         * big and cause kernel BTF validation failure if
                         * original variable took less than 4 bytes
                         */
                        t->size = 1;
                        *(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
                } else if (!has_datasec && btf_is_datasec(t)) {
                        /* replace DATASEC with STRUCT */
  [...]

The main changes are:

1) Addition of core parts of compile once - run everywhere (co-re) effort,
   that is, relocation of fields offsets in libbpf as well as exposure of
   kernel's own BTF via sysfs and loading through libbpf, from Andrii.

   More info on co-re: http://vger.kernel.org/bpfconf2019.html#session-2
   and http://vger.kernel.org/lpc-bpf2018.html#session-2

2) Enable passing input flags to the BPF flow dissector to customize parsing
   and allowing it to stop early similar to the C based one, from Stanislav.

3) Add a BPF helper function that allows generating SYN cookies from XDP and
   tc BPF, from Petar.

4) Add devmap hash-based map type for more flexibility in device lookup for
   redirects, from Toke.

5) Improvements to XDP forwarding sample code now utilizing recently enabled
   devmap lookups, from Jesper.

6) Add support for reporting the effective cgroup progs in bpftool, from Jakub
   and Takshak.

7) Fix reading kernel config from bpftool via /proc/config.gz, from Peter.

8) Fix AF_XDP umem pages mapping for 32 bit architectures, from Ivan.

9) Follow-up to add two more BPF loop tests for the selftest suite, from Alexei.

10) Add perf event output helper also for other skb-based program types, from Allan.

11) Fix a co-re related compilation error in selftests, from Yonghong.
====================

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

1 files changed, 53 insertions, 52 deletions

diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index d672d9086fff..03bdc5b3ac49 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -14,6 +14,7 @@
 
 #include <bpf.h>
 #include <libbpf.h>
+#include <zlib.h>
 
 #include "main.h"
 
@@ -284,34 +285,32 @@ static void probe_jit_limit(void)
 	}
 }
 
-static char *get_kernel_config_option(FILE *fd, const char *option)
+static bool read_next_kernel_config_option(gzFile file, char *buf, size_t n,
+					   char **value)
 {
-	size_t line_n = 0, optlen = strlen(option);
-	char *res, *strval, *line = NULL;
-	ssize_t n;
+	char *sep;
 
-	rewind(fd);
-	while ((n = getline(&line, &line_n, fd)) > 0) {
-		if (strncmp(line, option, optlen))
+	while (gzgets(file, buf, n)) {
+		if (strncmp(buf, "CONFIG_", 7))
 			continue;
-		/* Check we have at least '=', value, and '\n' */
-		if (strlen(line) < optlen + 3)
-			continue;
-		if (*(line + optlen) != '=')
+
+		sep = strchr(buf, '=');
+		if (!sep)
 			continue;
 
 		/* Trim ending '\n' */
-		line[strlen(line) - 1] = '\0';
+		buf[strlen(buf) - 1] = '\0';
+
+		/* Split on '=' and ensure that a value is present. */
+		*sep = '\0';
+		if (!sep[1])
+			continue;
 
-		/* Copy and return config option value */
-		strval = line + optlen + 1;
-		res = strdup(strval);
-		free(line);
-		return res;
+		*value = sep + 1;
+		return true;
 	}
-	free(line);
 
-	return NULL;
+	return false;
 }
 
 static void probe_kernel_image_config(void)
@@ -386,59 +385,61 @@ static void probe_kernel_image_config(void)
 		/* test_bpf module for BPF tests */
 		"CONFIG_TEST_BPF",
 	};
-	char *value, *buf = NULL;
+	char *values[ARRAY_SIZE(options)] = { };
 	struct utsname utsn;
 	char path[PATH_MAX];
-	size_t i, n;
-	ssize_t ret;
-	FILE *fd;
+	gzFile file = NULL;
+	char buf[4096];
+	char *value;
+	size_t i;
 
-	if (uname(&utsn))
-		goto no_config;
+	if (!uname(&utsn)) {
+		snprintf(path, sizeof(path), "/boot/config-%s", utsn.release);
 
-	snprintf(path, sizeof(path), "/boot/config-%s", utsn.release);
+		/* gzopen also accepts uncompressed files. */
+		file = gzopen(path, "r");
+	}
 
-	fd = fopen(path, "r");
-	if (!fd && errno == ENOENT) {
-		/* Some distributions put the config file at /proc/config, give
-		 * it a try.
-		 * Sometimes it is also at /proc/config.gz but we do not try
-		 * this one for now, it would require linking against libz.
+	if (!file) {
+		/* Some distributions build with CONFIG_IKCONFIG=y and put the
+		 * config file at /proc/config.gz.
 		 */
-		fd = fopen("/proc/config", "r");
+		file = gzopen("/proc/config.gz", "r");
 	}
-	if (!fd) {
+	if (!file) {
 		p_info("skipping kernel config, can't open file: %s",
 		       strerror(errno));
-		goto no_config;
+		goto end_parse;
 	}
 	/* Sanity checks */
-	ret = getline(&buf, &n, fd);
-	ret = getline(&buf, &n, fd);
-	if (!buf || !ret) {
+	if (!gzgets(file, buf, sizeof(buf)) ||
+	    !gzgets(file, buf, sizeof(buf))) {
 		p_info("skipping kernel config, can't read from file: %s",
 		       strerror(errno));
-		free(buf);
-		goto no_config;
+		goto end_parse;
 	}
 	if (strcmp(buf, "# Automatically generated file; DO NOT EDIT.\n")) {
 		p_info("skipping kernel config, can't find correct file");
-		free(buf);
-		goto no_config;
+		goto end_parse;
 	}
-	free(buf);
 
-	for (i = 0; i < ARRAY_SIZE(options); i++) {
-		value = get_kernel_config_option(fd, options[i]);
-		print_kernel_option(options[i], value);
-		free(value);
+	while (read_next_kernel_config_option(file, buf, sizeof(buf), &value)) {
+		for (i = 0; i < ARRAY_SIZE(options); i++) {
+			if (values[i] || strcmp(buf, options[i]))
+				continue;
+
+			values[i] = strdup(value);
+		}
 	}
-	fclose(fd);
-	return;
 
-no_config:
-	for (i = 0; i < ARRAY_SIZE(options); i++)
-		print_kernel_option(options[i], NULL);
+end_parse:
+	if (file)
+		gzclose(file);
+
+	for (i = 0; i < ARRAY_SIZE(options); i++) {
+		print_kernel_option(options[i], values[i]);
+		free(values[i]);
+	}
 }
 
 static bool probe_bpf_syscall(const char *define_prefix)