netdev - [PATCH bpf-next v2 13/13] bpfilter: Handle setsockopts

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Message-Id: <20210829183608.2297877-14-me@ubique.spb.ru>
Date:   Sun, 29 Aug 2021 22:36:08 +0400
From:   Dmitrii Banshchikov <me@...que.spb.ru>
To:     bpf@...r.kernel.org
Cc:     Dmitrii Banshchikov <me@...que.spb.ru>, ast@...nel.org,
        davem@...emloft.net, daniel@...earbox.net, andrii@...nel.org,
        kafai@...com, songliubraving@...com, yhs@...com,
        john.fastabend@...il.com, kpsingh@...nel.org,
        netdev@...r.kernel.org, rdna@...com
Subject: [PATCH bpf-next v2 13/13] bpfilter: Handle setsockopts

Use earlier introduced infrastructure and handle setsockopt(2) calls.

Signed-off-by: Dmitrii Banshchikov <me@...que.spb.ru>
---
 net/bpfilter/main.c | 126 +++++++++++++++++++++++++++++---------------
 1 file changed, 84 insertions(+), 42 deletions(-)

diff --git a/net/bpfilter/main.c b/net/bpfilter/main.c
index 291a92546246..1010e4c49716 100644
--- a/net/bpfilter/main.c
+++ b/net/bpfilter/main.c
@@ -1,64 +1,106 @@
 // SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 Telegram FZ-LLC
+ */
+
 #define _GNU_SOURCE
-#include <sys/uio.h>
+
+#include <unistd.h>
+#include <errno.h>
+
 #include <errno.h>
 #include <stdio.h>
-#include <sys/socket.h>
-#include <fcntl.h>
+#include <string.h>
 #include <unistd.h>
-#include "../../include/uapi/linux/bpf.h"
-#include <asm/unistd.h>
+
+#include "context.h"
+#include "filter-table.h"
 #include "msgfmt.h"
+#include "sockopt.h"
 
-FILE *debug_f;
+#define do_exact(fd, op, buffer, count)								\
+	({											\
+		size_t total = 0;                                                               \
+		int err = 0;									\
+												\
+		do {										\
+			const ssize_t part = op(fd, (buffer) + total, (count) - total);		\
+			if (part > 0) {								\
+				total += part;							\
+			} else if (part == 0 && (count) > 0) {					\
+				err = -EIO;							\
+				break;								\
+			} else if (part == -1) {						\
+				if (errno == EINTR)						\
+					continue;						\
+				err = -errno;							\
+				break;								\
+			}									\
+		} while (total < (count));							\
+												\
+		err;										\
+	})
 
-static int handle_get_cmd(struct mbox_request *cmd)
+static int read_exact(int fd, void *buffer, size_t count)
 {
-	switch (cmd->cmd) {
-	case 0:
-		return 0;
-	default:
-		break;
-	}
-	return -ENOPROTOOPT;
+	return do_exact(fd, read, buffer, count);
 }
 
-static int handle_set_cmd(struct mbox_request *cmd)
+static int write_exact(int fd, const void *buffer, size_t count)
 {
-	return -ENOPROTOOPT;
+	return do_exact(fd, write, buffer, count);
 }
 
-static void loop(void)
+static int setup_context(struct context *ctx)
 {
-	while (1) {
-		struct mbox_request req;
-		struct mbox_reply reply;
-		int n;
-
-		n = read(0, &req, sizeof(req));
-		if (n != sizeof(req)) {
-			fprintf(debug_f, "invalid request %d\n", n);
-			return;
-		}
-
-		reply.status = req.is_set ?
-			handle_set_cmd(&req) :
-			handle_get_cmd(&req);
-
-		n = write(1, &reply, sizeof(reply));
-		if (n != sizeof(reply)) {
-			fprintf(debug_f, "reply failed %d\n", n);
-			return;
-		}
+	ctx->log_file = fopen("/dev/kmsg", "w");
+	if (!ctx->log_file)
+		return -errno;
+
+	errno = 0;
+	if (setvbuf(ctx->log_file, 0, _IOLBF, 0))
+		return errno ? -errno : -EINVAL;
+
+	return create_filter_table(ctx);
+}
+
+static void loop(struct context *ctx)
+{
+	struct mbox_request req;
+	struct mbox_reply reply;
+	int err;
+
+	for (;;) {
+		err = read_exact(STDIN_FILENO, &req, sizeof(req));
+		if (err)
+			BFLOG_EMERG(ctx, "cannot read request: %s\n", strerror(-err));
+
+		reply.status = handle_sockopt_request(ctx, &req);
+
+		err = write_exact(STDOUT_FILENO, &reply, sizeof(reply));
+		if (err)
+			BFLOG_EMERG(ctx, "cannot write reply: %s\n", strerror(-err));
 	}
 }
 
 int main(void)
 {
-	debug_f = fopen("/dev/kmsg", "w");
-	setvbuf(debug_f, 0, _IOLBF, 0);
-	fprintf(debug_f, "<5>Started bpfilter\n");
-	loop();
-	fclose(debug_f);
+	struct context ctx;
+	int err;
+
+	err = create_context(&ctx);
+	if (err)
+		return err;
+
+	err = setup_context(&ctx);
+	if (err) {
+		free_context(&ctx);
+		return err;
+	}
+
+	BFLOG_NOTICE(&ctx, "started\n");
+
+	loop(&ctx);
+
 	return 0;
 }
-- 
2.25.1