Annotation of libaitio/src/bpf.c, revision 1.1.2.9
1.1.2.1 misho 1: #include "global.h"
2:
3:
1.1.2.2 misho 4: /*
5: * io_get1stiface() - Get first interface of host
6: *
7: * @szIface = interface string buffer
8: * @iflen = size of interface buffer
9: * return: -1 error or 0 ok
10: */
11: int
12: io_get1stiface(char *szIface, int iflen)
13: {
14: struct ifaddrs *ifa;
15:
16: if (!szIface || !iflen)
17: return -1;
18:
19: getifaddrs(&ifa);
20: strlcpy(szIface, ifa->ifa_name, iflen);
21: freeifaddrs(ifa);
22: return 0;
23: }
24:
25: /*
26: * io_etherClose() - Close BPF interface
27: *
28: * @eth = bpf handle
1.1.2.3 misho 29: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
1.1.2.2 misho 30: * return: none
31: */
32: void
1.1.2.3 misho 33: io_etherClose(int eth, void **zcbuf)
1.1.2.2 misho 34: {
1.1.2.3 misho 35: #ifdef __FreeBSD__
36: struct bpf_zbuf *zbuf = NULL;
37: #endif
38:
1.1.2.2 misho 39: if (eth > STDERR_FILENO)
40: close(eth);
1.1.2.3 misho 41:
42: if (zcbuf && *zcbuf) {
43: #ifdef __FreeBSD__
44: zbuf = *zcbuf;
45: munmap(zbuf->bz_bufb, zbuf->bz_buflen);
46: munmap(zbuf->bz_bufa, zbuf->bz_buflen);
47: e_free(*zcbuf);
48: *zcbuf = NULL;
49: #endif
50: }
51: }
52:
53: #ifdef __FreeBSD__
54: static inline struct bpf_zbuf *
55: allocZCbuf(u_int len)
56: {
57: struct bpf_zbuf *zbuf = NULL;
58:
59: zbuf = e_malloc(sizeof(struct bpf_zbuf));
60: if (!zbuf) {
61: io_SetErr(elwix_GetErrno(), "%s", elwix_GetError());
62: return NULL;
63: } else
64: memset(zbuf, 0, sizeof(struct bpf_zbuf));
65:
66: zbuf->bz_buflen = roundup(len, getpagesize());
67: zbuf->bz_bufa = mmap(NULL, zbuf->bz_buflen, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
68: if (zbuf->bz_bufa == MAP_FAILED) {
69: LOGERR;
70: e_free(zbuf);
71: return NULL;
72: } else
73: memset(zbuf->bz_bufa, 0, zbuf->bz_buflen);
74: zbuf->bz_bufb = mmap(NULL, zbuf->bz_buflen, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
75: if (zbuf->bz_bufb == MAP_FAILED) {
76: LOGERR;
77: munmap(zbuf->bz_bufa, zbuf->bz_buflen);
78: e_free(zbuf);
79: return NULL;
80: } else
81: memset(zbuf->bz_bufb, 0, zbuf->bz_buflen);
82:
83: return zbuf;
1.1.2.2 misho 84: }
1.1.2.3 misho 85: #endif
1.1.2.2 misho 86:
87: /*
88: * io_etherOpen() - Open BPF interface to device
89: *
90: * @csIface = interface name
91: * @flags = open flags
1.1.2.3 misho 92: * @whdr = with complete headers
93: * @buflen = buffer length
94: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
1.1.2.2 misho 95: * return: -1 error or >-1 bpf handle
96: */
97: int
1.1.2.4 misho 98: io_etherOpen(const char *csIface, int flags, int whdr, u_int *buflen, void **zcbuf)
1.1.2.2 misho 99: {
100: int n = 1, eth = -1;
101: register int i;
102: char szStr[STRSIZ];
103: struct ifreq ifr;
104:
105: for (i = 0; i < BPF_DEV_MAX; i++) {
106: memset(szStr, 0, sizeof szStr);
107: snprintf(szStr, sizeof szStr, "/dev/bpf%d", i);
108: eth = open(szStr, flags);
109: if (eth > STDERR_FILENO)
110: break;
111: }
112: if (eth < 3) {
113: LOGERR;
114: return -1;
115: }
116:
117: if (ioctl(eth, BIOCIMMEDIATE, &n) == -1) {
118: LOGERR;
119: close(eth);
120: return -1;
121: }
1.1.2.3 misho 122: if (whdr && ioctl(eth, BIOCSHDRCMPLT, &n) == -1) {
1.1.2.2 misho 123: LOGERR;
124: close(eth);
125: return -1;
126: }
1.1.2.4 misho 127: if (buflen && *buflen) {
1.1.2.3 misho 128: if (!zcbuf) {
1.1.2.4 misho 129: if (ioctl(eth, BIOCSBLEN, buflen) == -1) {
1.1.2.3 misho 130: LOGERR;
131: close(eth);
132: return -1;
133: }
134: } else {
135: #ifdef __FreeBSD__
136: n = BPF_BUFMODE_ZBUF;
137: if (ioctl(eth, BIOCSETBUFMODE, &n) == -1) {
138: LOGERR;
139: close(eth);
140: return -1;
141: }
142: if (ioctl(eth, BIOCGETZMAX, &n) == -1) {
143: LOGERR;
144: close(eth);
145: return -1;
1.1.2.5 misho 146: } else
147: *buflen = MIN(n, *buflen);
148: if (!(*zcbuf = allocZCbuf(*buflen))) {
1.1.2.3 misho 149: close(eth);
150: return -1;
151: }
152: if (ioctl(eth, BIOCSETZBUF, (struct bpf_zbuf*) *zcbuf) == -1) {
153: LOGERR;
154: io_etherClose(eth, zcbuf);
155: return -1;
156: }
157: #endif
158: }
159: }
1.1.2.2 misho 160: if (csIface)
161: strlcpy(szStr, csIface, sizeof szStr);
162: else if (io_get1stiface(szStr, sizeof szStr) == -1) {
1.1.2.3 misho 163: io_etherClose(eth, zcbuf);
1.1.2.2 misho 164: return -1;
165: }
166: strlcpy(ifr.ifr_name, szStr, sizeof ifr.ifr_name);
167: if (ioctl(eth, BIOCSETIF, &ifr) == -1) {
168: LOGERR;
1.1.2.3 misho 169: io_etherClose(eth, zcbuf);
1.1.2.2 misho 170: return -1;
171: }
172:
173: return eth;
174: }
1.1.2.6 misho 175:
176: /*
177: * io_etherSend() - Send packet to bpf
178: *
179: * @eth = bpf handle
180: * @buf = buffer
181: * @buflen = buffer length
182: * return: -1 error or !=-1 written bytes
183: */
184: ssize_t
185: io_etherSend(int eth, const void *buf, size_t buflen)
186: {
187: ssize_t wlen = 0;
188:
189: if (!buf || !buflen) {
190: io_SetErr(EINVAL, "invalid arguments");
191: return -1;
192: }
193:
194: wlen = write(eth, buf, buflen);
195: if (wlen == -1)
196: LOGERR;
197: return wlen;
198: }
199:
200: #ifdef __FreeBSD__
1.1.2.8 misho 201: static inline void
202: ackZCbuf(struct bpf_zbuf_header * __restrict bzh)
203: {
204: atomic_store_rel_int(&bzh->bzh_user_gen, bzh->bzh_kernel_gen);
205: }
206:
207: static inline int
208: chkZCbuf(struct bpf_zbuf_header * __restrict bzh)
209: {
210: /* return true if userspace owns buffer, and false otherwise. */
211: return (bzh->bzh_user_gen != atomic_load_acq_int(&bzh->bzh_kernel_gen));
212: }
213:
1.1.2.6 misho 214: static inline ssize_t
1.1.2.7 misho 215: nextZCbuf(void ** __restrict zcache, struct bpf_zbuf * __restrict zbuf,
216: const void * __restrict buf)
1.1.2.6 misho 217: {
218: ssize_t rlen = -1;
219: struct bpf_zbuf_header *bzh;
220:
221: if (!*zcache || *zcache == zbuf->bz_bufb) {
222: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufa;
1.1.2.8 misho 223: if (chkZCbuf(bzh)) {
1.1.2.6 misho 224: rlen = atomic_load_acq_int(&bzh->bzh_kernel_len);
225: *zcache = zbuf->bz_bufa;
1.1.2.7 misho 226: if (buf)
227: buf = ((caddr_t) *zcache) + sizeof(struct bpf_zbuf_header);
1.1.2.8 misho 228: ackZCbuf(bzh);
1.1.2.9 ! misho 229: } else
! 230: io_SetErr(EAGAIN, "kernel owns the buffer");
1.1.2.6 misho 231: } else if (*zcache == zbuf->bz_bufa) {
232: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufb;
1.1.2.8 misho 233: if (chkZCbuf(bzh)) {
1.1.2.6 misho 234: rlen = atomic_load_acq_int(&bzh->bzh_kernel_len);
235: *zcache = zbuf->bz_bufb;
1.1.2.7 misho 236: if (buf)
237: buf = ((caddr_t) *zcache) + sizeof(struct bpf_zbuf_header);
1.1.2.8 misho 238: ackZCbuf(bzh);
1.1.2.9 ! misho 239: } else
! 240: io_SetErr(EAGAIN, "kernel owns the buffer");
1.1.2.6 misho 241: }
242:
243: return rlen;
244: }
245: #endif
246:
247: /*
248: * io_etherRecv() - Receive packet from bpf
249: *
250: * @eth = bpf handle
251: * @buf = buffer
252: * @buflen = buffer length
253: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
254: * return: -1 error or !=-1 readed bytes
255: */
256: ssize_t
257: io_etherRecv(int eth, void * __restrict buf, size_t buflen, void * __restrict zcbuf)
258: {
259: ssize_t rlen = 0;
260: void **zcache = NULL;
261:
262: if (!buf || !buflen) {
263: io_SetErr(EINVAL, "invalid arguments");
264: return -1;
265: }
266:
267: if (!zcbuf) {
268: rlen = read(eth, buf, buflen);
269: if (rlen == -1)
270: LOGERR;
271: } else {
272: #ifdef __FreeBSD__
1.1.2.7 misho 273: rlen = nextZCbuf(zcache, (struct bpf_zbuf*) zcbuf, buf);
1.1.2.6 misho 274: #else
275: io_SetErr(ENOTSUP, "bpf zero copy buffer mode is not supported");
276: #endif
277: }
278:
279: return rlen;
280: }
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