1: #include "global.h"
2:
3:
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
29: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
30: * return: none
31: */
32: void
33: io_etherClose(int eth, void **zcbuf)
34: {
35: #ifdef __FreeBSD__
36: struct bpf_zbuf *zbuf = NULL;
37: #endif
38:
39: if (eth > STDERR_FILENO)
40: close(eth);
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;
84: }
85: #endif
86:
87: /*
88: * io_etherOpen() - Open BPF interface to device
89: *
90: * @csIface = interface name
91: * @flags = open flags
92: * @whdr = with complete headers
93: * @buflen = buffer length
94: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
95: * return: -1 error or >-1 bpf handle
96: */
97: int
98: io_etherOpen(const char *csIface, int flags, int whdr, u_int *buflen, void **zcbuf)
99: {
100: int eth = -1;
101: register int i;
102: char szStr[STRSIZ];
103: struct ifreq ifr;
104: u_int n = 1;
105:
106: #ifndef __FreeBSD__
107: if (zcbuf) {
108: io_SetErr(ENOTSUP, "bpf zero copy buffer mode is not supported");
109: return -1;
110: }
111: #endif
112:
113: for (i = 0; i < BPF_DEV_MAX; i++) {
114: memset(szStr, 0, sizeof szStr);
115: snprintf(szStr, sizeof szStr, "/dev/bpf%d", i);
116: eth = open(szStr, flags);
117: if (eth > STDERR_FILENO)
118: break;
119: }
120: if (eth < 3) {
121: LOGERR;
122: return -1;
123: }
124:
125: if (!zcbuf) {
126: if (ioctl(eth, BIOCGBLEN, &n) == -1) {
127: LOGERR;
128: close(eth);
129: return -1;
130: } else
131: n = (buflen && *buflen) ? *buflen : n;
132: if (ioctl(eth, BIOCSBLEN, &n) == -1) {
133: LOGERR;
134: close(eth);
135: return -1;
136: }
137: if (buflen && *buflen)
138: *buflen = n;
139: } else {
140: #ifdef __FreeBSD__
141: n = BPF_BUFMODE_ZBUF;
142: if (ioctl(eth, BIOCSETBUFMODE, &n) == -1) {
143: LOGERR;
144: close(eth);
145: return -1;
146: }
147: if (ioctl(eth, BIOCGETZMAX, &n) == -1) {
148: LOGERR;
149: close(eth);
150: return -1;
151: } else
152: n = (buflen && *buflen) ? *buflen : n;
153: if (!(*zcbuf = allocZCbuf(n))) {
154: close(eth);
155: return -1;
156: }
157: if (ioctl(eth, BIOCSETZBUF, (struct bpf_zbuf*) *zcbuf) == -1) {
158: LOGERR;
159: io_etherClose(eth, zcbuf);
160: return -1;
161: }
162: if (buflen && *buflen)
163: *buflen = n;
164: #endif
165: }
166:
167: if (csIface)
168: strlcpy(szStr, csIface, sizeof szStr);
169: else if (io_get1stiface(szStr, sizeof szStr) == -1) {
170: io_etherClose(eth, zcbuf);
171: return -1;
172: }
173: memset(&ifr, 0, sizeof ifr);
174: strlcpy(ifr.ifr_name, szStr, sizeof ifr.ifr_name);
175: if (ioctl(eth, BIOCSETIF, &ifr) == -1) {
176: LOGERR;
177: io_etherClose(eth, zcbuf);
178: return -1;
179: }
180:
181: n = 1;
182: if (whdr && ioctl(eth, BIOCSHDRCMPLT, &n) == -1) {
183: LOGERR;
184: io_etherClose(eth, zcbuf);
185: return -1;
186: }
187: if (ioctl(eth, BIOCIMMEDIATE, &n) == -1) {
188: LOGERR;
189: io_etherClose(eth, zcbuf);
190: return -1;
191: }
192:
193: return eth;
194: }
195:
196: /*
197: * io_etherSend() - Send packet to bpf
198: *
199: * @eth = bpf handle
200: * @buf = buffer
201: * @buflen = buffer length
202: * return: -1 error or !=-1 written bytes
203: */
204: ssize_t
205: io_etherSend(int eth, const void *buf, size_t buflen)
206: {
207: ssize_t wlen = 0;
208:
209: if (!buf || !buflen) {
210: io_SetErr(EINVAL, "invalid arguments");
211: return -1;
212: }
213:
214: wlen = write(eth, buf, buflen);
215: if (wlen == -1)
216: LOGERR;
217: return wlen;
218: }
219:
220: #ifdef __FreeBSD__
221: static inline void
222: ackZCbuf(struct bpf_zbuf_header * __restrict bzh)
223: {
224: atomic_store_rel_int(&bzh->bzh_user_gen, bzh->bzh_kernel_gen);
225: }
226:
227: static inline int
228: chkZCbuf(struct bpf_zbuf_header * __restrict bzh)
229: {
230: /* return true if userspace owns buffer, and false otherwise. */
231: return (bzh->bzh_user_gen != atomic_load_acq_int(&bzh->bzh_kernel_gen));
232: }
233:
234: static inline ssize_t
235: nextZCbuf(void ** __restrict zcache, struct bpf_zbuf * __restrict zbuf,
236: const void * __restrict buf)
237: {
238: ssize_t rlen = -1;
239: struct bpf_zbuf_header *bzh;
240:
241: if (!*zcache || *zcache == zbuf->bz_bufb) {
242: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufa;
243: if (chkZCbuf(bzh)) {
244: rlen = atomic_load_acq_int(&bzh->bzh_kernel_len);
245: *zcache = zbuf->bz_bufa;
246: if (buf)
247: buf = ((caddr_t) *zcache) + sizeof(struct bpf_zbuf_header);
248: ackZCbuf(bzh);
249: } else
250: io_SetErr(EAGAIN, "kernel owns the buffer A");
251: } else if (*zcache == zbuf->bz_bufa) {
252: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufb;
253: if (chkZCbuf(bzh)) {
254: rlen = atomic_load_acq_int(&bzh->bzh_kernel_len);
255: *zcache = zbuf->bz_bufb;
256: if (buf)
257: buf = ((caddr_t) *zcache) + sizeof(struct bpf_zbuf_header);
258: ackZCbuf(bzh);
259: } else
260: io_SetErr(EAGAIN, "kernel owns the buffer B");
261: }
262:
263: return rlen;
264: }
265: #endif
266:
267: /*
268: * io_etherRecv() - Receive packet from bpf
269: *
270: * @eth = bpf handle
271: * @buf = buffer
272: * @buflen = buffer length
273: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
274: * return: -1 error or !=-1 readed bytes
275: */
276: ssize_t
277: io_etherRecv(int eth, void * __restrict buf, size_t buflen, void * __restrict zcbuf)
278: {
279: ssize_t rlen = 0;
280: void *zcache = NULL;
281:
282: if (!buf || !buflen) {
283: io_SetErr(EINVAL, "invalid arguments");
284: return -1;
285: }
286:
287: if (!zcbuf) {
288: rlen = read(eth, buf, buflen);
289: if (rlen == -1)
290: LOGERR;
291: } else {
292: #ifdef __FreeBSD__
293: rlen = nextZCbuf(&zcache, (struct bpf_zbuf*) zcbuf, buf);
294: #else
295: io_SetErr(ENOTSUP, "bpf zero copy buffer mode is not supported");
296: #endif
297: }
298:
299: return rlen;
300: }
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