diff options
Diffstat (limited to 'pcap_sg.c')
| -rw-r--r-- | pcap_sg.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/pcap_sg.c b/pcap_sg.c new file mode 100644 index 0000000..ad78ce7 --- /dev/null +++ b/pcap_sg.c @@ -0,0 +1,193 @@ +/* + * 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 "xio.h" +#include "xutils.h" +#include "built_in.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; + } + + fmemcpy(iov[iov_slot].iov_base, &phdr->raw, hdrsize); + iov[iov_slot].iov_len = hdrsize; + + fmemcpy(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, enum pcap_type type, + uint8_t *packet, size_t len, 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); + + fmemcpy(&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; + } + + fmemcpy(&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 len, 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); + + fmemcpy(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; + } + + fmemcpy(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)) { + fmemcpy(&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, type, packet, + len, 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)) { + fmemcpy(packet, iov[iov_slot].iov_base + iov_off_rd, hdrlen); + iov_off_rd += hdrlen; + } else { + ret = __pcap_sg_inter_iov_data_read(fd, packet, len, 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 int pcap_sg_prepare_access(int fd, enum pcap_mode mode, bool jumbo) +{ + int i, ret; + size_t len = 0; + + iov_slot = 0; + len = jumbo ? (PAGE_SIZE * 16) /* 64k max */ : + (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; + } + + set_ioprio_rt(); + + 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, enum pcap_mode mode) +{ + int i; + + for (i = 0; i < array_size(iov); ++i) + xfree(iov[i].iov_base); +} + +const struct pcap_file_ops pcap_sg_ops = { + .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, +}; |