tools/testing/selftests/net/txring_overwrite.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/net/txring_overwrite.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/net/txring_overwrite.c
Extension
.c
Size
3807 bytes
Lines
180
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0

/*
 * Verify that consecutive sends over packet tx_ring are mirrored
 * with their original content intact.
 */

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <assert.h>
#include <error.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/filter.h>
#include <linux/if_packet.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <poll.h>
#include <pthread.h>
#include <sched.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/utsname.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

const int eth_off = TPACKET_HDRLEN - sizeof(struct sockaddr_ll);
const int cfg_frame_size = 1000;

static void build_packet(void *buffer, size_t blen, char payload_char)
{
	struct udphdr *udph;
	struct ethhdr *eth;
	struct iphdr *iph;
	size_t off = 0;

	memset(buffer, 0, blen);

	eth = buffer;
	eth->h_proto = htons(ETH_P_IP);

	off += sizeof(*eth);
	iph = buffer + off;
	iph->ttl	= 8;
	iph->ihl	= 5;
	iph->version	= 4;
	iph->saddr	= htonl(INADDR_LOOPBACK);
	iph->daddr	= htonl(INADDR_LOOPBACK + 1);
	iph->protocol	= IPPROTO_UDP;
	iph->tot_len	= htons(blen - off);
	iph->check	= 0;

	off += sizeof(*iph);
	udph = buffer + off;
	udph->dest	= htons(8000);
	udph->source	= htons(8001);
	udph->len	= htons(blen - off);
	udph->check	= 0;

	off += sizeof(*udph);
	memset(buffer + off, payload_char, blen - off);
}

static int setup_rx(void)
{
	int fdr;

	fdr = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_IP));
	if (fdr == -1)
		error(1, errno, "socket r");

	return fdr;
}

static int setup_tx(char **ring)
{
	struct sockaddr_ll laddr = {};
	struct tpacket_req req = {};
	int fdt;

Annotation

Implementation Notes