build: Add Makefile target for Coverity scanner
[netsniff-ng.git] / pcap_sg.c
blob7a2bfb0d7150bccfc43a3fc4f74475517c3a09cd
1 /*
2 * netsniff-ng - the packet sniffing beast
3 * Copyright 2011 - 2013 Daniel Borkmann.
4 * Subject to the GPL, version 2.
5 */
7 #include <stdio.h>
8 #include <sys/types.h>
9 #include <sys/stat.h>
10 #include <fcntl.h>
11 #include <sys/uio.h>
12 #include <unistd.h>
14 #include "pcap_io.h"
15 #include "xmalloc.h"
16 #include "built_in.h"
17 #include "iosched.h"
18 #include "ioops.h"
20 static struct iovec iov[1024] __cacheline_aligned;
21 static off_t iov_off_rd = 0, iov_slot = 0;
23 static ssize_t pcap_sg_write(int fd, pcap_pkthdr_t *phdr, enum pcap_type type,
24 const uint8_t *packet, size_t len)
26 ssize_t ret, hdrsize = pcap_get_hdr_length(phdr, type);
28 if (unlikely(iov_slot == array_size(iov))) {
29 ret = writev(fd, iov, array_size(iov));
30 if (ret < 0)
31 panic("Writev I/O error: %s!\n", strerror(errno));
33 iov_slot = 0;
36 fmemcpy(iov[iov_slot].iov_base, &phdr->raw, hdrsize);
37 iov[iov_slot].iov_len = hdrsize;
39 fmemcpy(iov[iov_slot].iov_base + iov[iov_slot].iov_len, packet, len);
40 ret = (iov[iov_slot].iov_len += len);
42 iov_slot++;
43 return ret;
46 static ssize_t __pcap_sg_inter_iov_hdr_read(int fd, pcap_pkthdr_t *phdr,
47 size_t hdrsize)
49 int ret;
50 size_t offset = 0;
51 ssize_t remainder;
53 offset = iov[iov_slot].iov_len - iov_off_rd;
54 remainder = hdrsize - offset;
55 if (remainder < 0)
56 remainder = 0;
58 bug_on(offset + remainder != hdrsize);
60 fmemcpy(&phdr->raw, iov[iov_slot].iov_base + iov_off_rd, offset);
61 iov_off_rd = 0;
62 iov_slot++;
64 if (iov_slot == array_size(iov)) {
65 iov_slot = 0;
66 ret = readv(fd, iov, array_size(iov));
67 if (unlikely(ret <= 0))
68 return -EIO;
71 fmemcpy(&phdr->raw + offset, iov[iov_slot].iov_base + iov_off_rd, remainder);
72 iov_off_rd += remainder;
74 return hdrsize;
77 static ssize_t __pcap_sg_inter_iov_data_read(int fd, uint8_t *packet, size_t hdrlen)
79 int ret;
80 size_t offset = 0;
81 ssize_t remainder;
83 offset = iov[iov_slot].iov_len - iov_off_rd;
84 remainder = hdrlen - offset;
85 if (remainder < 0)
86 remainder = 0;
88 bug_on(offset + remainder != hdrlen);
90 fmemcpy(packet, iov[iov_slot].iov_base + iov_off_rd, offset);
91 iov_off_rd = 0;
92 iov_slot++;
94 if (iov_slot == array_size(iov)) {
95 iov_slot = 0;
96 ret = readv(fd, iov, array_size(iov));
97 if (unlikely(ret <= 0))
98 return -EIO;
101 fmemcpy(packet + offset, iov[iov_slot].iov_base + iov_off_rd, remainder);
102 iov_off_rd += remainder;
104 return hdrlen;
107 static ssize_t pcap_sg_read(int fd, pcap_pkthdr_t *phdr, enum pcap_type type,
108 uint8_t *packet, size_t len)
110 ssize_t ret = 0;
111 size_t hdrsize = pcap_get_hdr_length(phdr, type), hdrlen;
113 if (likely(iov[iov_slot].iov_len - iov_off_rd >= hdrsize)) {
114 fmemcpy(&phdr->raw, iov[iov_slot].iov_base + iov_off_rd, hdrsize);
115 iov_off_rd += hdrsize;
116 } else {
117 ret = __pcap_sg_inter_iov_hdr_read(fd, phdr, hdrsize);
118 if (unlikely(ret < 0))
119 return ret;
122 hdrlen = pcap_get_length(phdr, type);
123 if (unlikely(hdrlen == 0 || hdrlen > len))
124 return -EINVAL;
126 if (likely(iov[iov_slot].iov_len - iov_off_rd >= hdrlen)) {
127 fmemcpy(packet, iov[iov_slot].iov_base + iov_off_rd, hdrlen);
128 iov_off_rd += hdrlen;
129 } else {
130 ret = __pcap_sg_inter_iov_data_read(fd, packet, hdrlen);
131 if (unlikely(ret < 0))
132 return ret;
135 return hdrsize + hdrlen;
138 static void pcap_sg_fsync(int fd)
140 ssize_t ret = writev(fd, iov, iov_slot);
141 if (ret < 0)
142 panic("Writev I/O error: %s!\n", strerror(errno));
144 iov_slot = 0;
145 fdatasync(fd);
148 static void pcap_sg_init_once(void)
150 set_ioprio_rt();
153 static int pcap_sg_prepare_access(int fd, enum pcap_mode mode, bool jumbo)
155 int ret;
156 size_t i, len = 0;
158 iov_slot = 0;
159 len = jumbo ? (PAGE_SIZE * 16) /* 64k max */ :
160 (PAGE_SIZE * 3) /* 12k max */;
162 for (i = 0; i < array_size(iov); ++i) {
163 iov[i].iov_base = xzmalloc_aligned(len, 64);
164 iov[i].iov_len = len;
167 if (mode == PCAP_MODE_RD) {
168 ret = readv(fd, iov, array_size(iov));
169 if (ret <= 0)
170 return -EIO;
172 iov_off_rd = 0;
173 iov_slot = 0;
176 return 0;
179 static void pcap_sg_prepare_close(int fd __maybe_unused,
180 enum pcap_mode mode __maybe_unused)
182 size_t i;
184 for (i = 0; i < array_size(iov); ++i)
185 xfree(iov[i].iov_base);
188 const struct pcap_file_ops pcap_sg_ops = {
189 .init_once_pcap = pcap_sg_init_once,
190 .pull_fhdr_pcap = pcap_generic_pull_fhdr,
191 .push_fhdr_pcap = pcap_generic_push_fhdr,
192 .prepare_access_pcap = pcap_sg_prepare_access,
193 .prepare_close_pcap = pcap_sg_prepare_close,
194 .read_pcap = pcap_sg_read,
195 .write_pcap = pcap_sg_write,
196 .fsync_pcap = pcap_sg_fsync,