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/*
* netsniff-ng - the packet sniffing beast
* Copyright 2011 - 2013 Daniel Borkmann.
* Subject to the GPL, version 2.
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/uio.h>
#include <unistd.h>
#include "pcap_io.h"
#include "xmalloc.h"
#include "built_in.h"
#include "iosched.h"
#include "ioops.h"
static struct iovec iov[1024] __cacheline_aligned;
static off_t iov_off_rd = 0, iov_slot = 0;
static ssize_t pcap_sg_write(int fd, pcap_pkthdr_t *phdr, enum pcap_type type,
const uint8_t *packet, size_t len)
{
ssize_t ret, hdrsize = pcap_get_hdr_length(phdr, type);
if (unlikely(iov_slot == array_size(iov))) {
ret = writev(fd, iov, array_size(iov));
if (ret < 0)
panic("Writev I/O error: %s!\n", strerror(errno));
iov_slot = 0;
}
memcpy(iov[iov_slot].iov_base, &phdr->raw, hdrsize);
iov[iov_slot].iov_len = hdrsize;
memcpy(iov[iov_slot].iov_base + iov[iov_slot].iov_len, packet, len);
ret = (iov[iov_slot].iov_len += len);
iov_slot++;
return ret;
}
static ssize_t __pcap_sg_inter_iov_hdr_read(int fd, pcap_pkthdr_t *phdr,
size_t hdrsize)
{
int ret;
size_t offset = 0;
ssize_t remainder;
offset = iov[iov_slot].iov_len - iov_off_rd;
remainder = hdrsize - offset;
if (remainder < 0)
remainder = 0;
bug_on(offset + remainder != hdrsize);
memcpy(&phdr->raw, iov[iov_slot].iov_base + iov_off_rd, offset);
iov_off_rd = 0;
iov_slot++;
if (iov_slot == array_size(iov)) {
iov_slot = 0;
ret = readv(fd, iov, array_size(iov));
if (unlikely(ret <= 0))
return -EIO;
}
memcpy(&phdr->raw + offset, iov[iov_slot].iov_base + iov_off_rd, remainder);
iov_off_rd += remainder;
return hdrsize;
}
static ssize_t __pcap_sg_inter_iov_data_read(int fd, uint8_t *packet, size_t hdrlen)
{
int ret;
size_t offset = 0;
ssize_t remainder;
offset = iov[iov_slot].iov_len - iov_off_rd;
remainder = hdrlen - offset;
if (remainder < 0)
remainder = 0;
bug_on(offset + remainder != hdrlen);
memcpy(packet, iov[iov_slot].iov_base + iov_off_rd, offset);
iov_off_rd = 0;
iov_slot++;
if (iov_slot == array_size(iov)) {
iov_slot = 0;
ret = readv(fd, iov, array_size(iov));
if (unlikely(ret <= 0))
return -EIO;
}
memcpy(packet + offset, iov[iov_slot].iov_base + iov_off_rd, remainder);
iov_off_rd += remainder;
return hdrlen;
}
static ssize_t pcap_sg_read(int fd, pcap_pkthdr_t *phdr, enum pcap_type type,
uint8_t *packet, size_t len)
{
ssize_t ret = 0;
size_t hdrsize = pcap_get_hdr_length(phdr, type), hdrlen;
if (likely(iov[iov_slot].iov_len - iov_off_rd >= hdrsize)) {
memcpy(&phdr->raw, iov[iov_slot].iov_base + iov_off_rd, hdrsize);
iov_off_rd += hdrsize;
} else {
ret = __pcap_sg_inter_iov_hdr_read(fd, phdr, hdrsize);
if (unlikely(ret < 0))
return ret;
}
hdrlen = pcap_get_length(phdr, type);
if (unlikely(hdrlen == 0 || hdrlen > len))
return -EINVAL;
if (likely(iov[iov_slot].iov_len - iov_off_rd >= hdrlen)) {
memcpy(packet, iov[iov_slot].iov_base + iov_off_rd, hdrlen);
iov_off_rd += hdrlen;
} else {
ret = __pcap_sg_inter_iov_data_read(fd, packet, hdrlen);
if (unlikely(ret < 0))
return ret;
}
return hdrsize + hdrlen;
}
static void pcap_sg_fsync(int fd)
{
ssize_t ret = writev(fd, iov, iov_slot);
if (ret < 0)
panic("Writev I/O error: %s!\n", strerror(errno));
iov_slot = 0;
fdatasync(fd);
}
static void pcap_sg_init_once(bool enforce_prio)
{
if (enforce_prio)
set_ioprio_rt();
}
static int pcap_sg_prepare_access(int fd, enum pcap_mode mode, bool jumbo)
{
int ret;
size_t i, len = 0;
iov_slot = 0;
len = jumbo ? (RUNTIME_PAGE_SIZE * 16) /* 64k max */ :
(RUNTIME_PAGE_SIZE * 3) /* 12k max */;
for (i = 0; i < array_size(iov); ++i) {
iov[i].iov_base = xzmalloc_aligned(len, 64);
iov[i].iov_len = len;
}
if (mode == PCAP_MODE_RD) {
ret = readv(fd, iov, array_size(iov));
if (ret <= 0)
return -EIO;
iov_off_rd = 0;
iov_slot = 0;
}
return 0;
}
static void pcap_sg_prepare_close(int fd __maybe_unused,
enum pcap_mode mode __maybe_unused)
{
size_t i;
for (i = 0; i < array_size(iov); ++i)
xfree(iov[i].iov_base);
}
const struct pcap_file_ops pcap_sg_ops = {
.init_once_pcap = pcap_sg_init_once,
.pull_fhdr_pcap = pcap_generic_pull_fhdr,
.push_fhdr_pcap = pcap_generic_push_fhdr,
.prepare_access_pcap = pcap_sg_prepare_access,
.prepare_close_pcap = pcap_sg_prepare_close,
.read_pcap = pcap_sg_read,
.write_pcap = pcap_sg_write,
.fsync_pcap = pcap_sg_fsync,
};
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