xref: /dragonfly/sys/net/netmap/netmap_user.h (revision f933b737)
1 /*
2  * Copyright (C) 2011 Matteo Landi, Luigi Rizzo. All rights reserved.
3  * Copyright (C) 2013 Universita` di Pisa
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  *   1. Redistributions of source code must retain the above copyright
10  *      notice, this list of conditions and the following disclaimer.
11  *   2. Redistributions in binary form must reproduce the above copyright
12  *      notice, this list of conditions and the following disclaimer in the
13  *      documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 /*
29  * $FreeBSD$
30  *
31  * This header contains the macros used to manipulate netmap structures
32  * and packets in userspace. See netmap(4) for more information.
33  *
34  * The address of the struct netmap_if, say nifp, is computed from the
35  * value returned from ioctl(.., NIOCREG, ...) and the mmap region:
36  *	ioctl(fd, NIOCREG, &req);
37  *	mem = mmap(0, ... );
38  *	nifp = NETMAP_IF(mem, req.nr_nifp);
39  *		(so simple, we could just do it manually)
40  *
41  * From there:
42  *	struct netmap_ring *NETMAP_TXRING(nifp, index)
43  *	struct netmap_ring *NETMAP_RXRING(nifp, index)
44  *		we can access ring->nr_cur, ring->nr_avail, ring->nr_flags
45  *
46  *	ring->slot[i] gives us the i-th slot (we can access
47  *		directly plen, flags, bufindex)
48  *
49  *	char *buf = NETMAP_BUF(ring, x) returns a pointer to
50  *		the buffer numbered x
51  *
52  * Since rings are circular, we have macros to compute the next index
53  *	i = NETMAP_RING_NEXT(ring, i);
54  *
55  * To ease porting apps from pcap to netmap we supply a few fuctions
56  * that can be called to open, close and read from netmap in a way
57  * similar to libpcap.
58  *
59  * In order to use these, include #define NETMAP_WITH_LIBS
60  * in the source file that invokes these functions.
61  */
62 
63 #ifndef _NET_NETMAP_USER_H_
64 #define _NET_NETMAP_USER_H_
65 
66 #include <stdint.h>
67 #include <net/if.h>		/* IFNAMSIZ */
68 #include <net/netmap/netmap.h>
69 
70 #define _NETMAP_OFFSET(type, ptr, offset) \
71 	((type)(void *)((char *)(ptr) + (offset)))
72 
73 #define NETMAP_IF(b, o)	_NETMAP_OFFSET(struct netmap_if *, b, o)
74 
75 #define NETMAP_TXRING(nifp, index) _NETMAP_OFFSET(struct netmap_ring *, \
76 	nifp, (nifp)->ring_ofs[index] )
77 
78 #define NETMAP_RXRING(nifp, index) _NETMAP_OFFSET(struct netmap_ring *,	\
79 	nifp, (nifp)->ring_ofs[index + (nifp)->ni_tx_rings + 1] )
80 
81 #define NETMAP_BUF(ring, index)				\
82 	((char *)(ring) + (ring)->buf_ofs + ((index)*(ring)->nr_buf_size))
83 
84 #define NETMAP_BUF_IDX(ring, buf)			\
85 	( ((char *)(buf) - ((char *)(ring) + (ring)->buf_ofs) ) / \
86 		(ring)->nr_buf_size )
87 
88 #define	NETMAP_RING_NEXT(r, i)				\
89 	((i)+1 == (r)->num_slots ? 0 : (i) + 1 )
90 
91 #define	NETMAP_RING_FIRST_RESERVED(r)			\
92 	( (r)->cur < (r)->reserved ?			\
93 	  (r)->cur + (r)->num_slots - (r)->reserved :	\
94 	  (r)->cur - (r)->reserved )
95 
96 /*
97  * Return 1 if the given tx ring is empty.
98  */
99 #define NETMAP_TX_RING_EMPTY(r)	((r)->avail >= (r)->num_slots - 1)
100 
101 #ifdef NETMAP_WITH_LIBS
102 /*
103  * Support for simple I/O libraries.
104  * Include other system headers required for compiling this.
105  */
106 
107 #ifndef HAVE_NETMAP_WITH_LIBS
108 #define HAVE_NETMAP_WITH_LIBS
109 
110 #include <sys/time.h>
111 #include <sys/mman.h>
112 #include <string.h>	/* memset */
113 #include <sys/ioctl.h>
114 #include <sys/errno.h>	/* EINVAL */
115 #include <fcntl.h>	/* O_RDWR */
116 #include <stdlib.h>
117 
118 struct nm_hdr_t {	/* same as pcap_pkthdr */
119 	struct timeval	ts;
120 	uint32_t	caplen;
121 	uint32_t	len;
122 };
123 
124 struct nm_desc_t {
125 	struct nm_desc_t *self;
126 	int fd;
127 	void *mem;
128 	int memsize;
129 	struct netmap_if *nifp;
130 	uint16_t first_ring, last_ring, cur_ring;
131 	struct nmreq req;
132 	struct nm_hdr_t hdr;
133 };
134 
135 /*
136  * when the descriptor is open correctly, d->self == d
137  */
138 #define P2NMD(p)		((struct nm_desc_t *)(p))
139 #define IS_NETMAP_DESC(d)	(P2NMD(d)->self == P2NMD(d))
140 #define NETMAP_FD(d)		(P2NMD(d)->fd)
141 
142 /*
143  * The callback, invoked on each received packet. Same as libpcap
144  */
145 typedef void (*nm_cb_t)(u_char *, const struct nm_hdr_t *, const u_char *d);
146 
147 /*
148  * The open routine accepts an ifname (netmap:foo or vale:foo) and
149  * optionally a second (string) argument indicating the ring number
150  * to open. If successful, t opens the fd and maps the memory.
151  */
152 static struct nm_desc_t *nm_open(const char *ifname,
153 	 const char *ring_no, int flags, int ring_flags);
154 
155 /*
156  * nm_dispatch() is the same as pcap_dispatch()
157  * nm_next() is the same as pcap_next()
158  */
159 static int nm_dispatch(struct nm_desc_t *, int, nm_cb_t, u_char *);
160 static u_char *nm_next(struct nm_desc_t *, struct nm_hdr_t *);
161 
162 /*
163  * unmap memory, close file descriptor and free the descriptor.
164  */
165 static int nm_close(struct nm_desc_t *);
166 
167 
168 /*
169  * Try to open, return descriptor if successful, NULL otherwise.
170  * An invalid netmap name will return errno = 0;
171  */
172 static struct nm_desc_t *
nm_open(const char * ifname,const char * ring_name,int flags,int ring_flags)173 nm_open(const char *ifname, const char *ring_name, int flags, int ring_flags)
174 {
175 	struct nm_desc_t *d;
176 	u_int n;
177 
178 	if (strncmp(ifname, "netmap:", 7) && strncmp(ifname, "vale", 4)) {
179 		errno = 0; /* name not recognised */
180 		return NULL;
181 	}
182 	if (ifname[0] == 'n')
183 		ifname += 7;
184 	d = (struct nm_desc_t *)calloc(1, sizeof(*d));
185 	if (d == NULL) {
186 		errno = ENOMEM;
187 		return NULL;
188 	}
189 	d->self = d;	/* set this early so nm_close() works */
190 	d->fd = open("/dev/netmap", O_RDWR);
191 	if (d->fd < 0)
192 		goto fail;
193 
194 	if (flags & NETMAP_SW_RING) {
195 		d->req.nr_ringid = NETMAP_SW_RING;
196 	} else {
197 		u_int r;
198 		if (flags & NETMAP_HW_RING) /* interpret ring as int */
199 			r = (uintptr_t)ring_name;
200 		else /* interpret ring as numeric string */
201 			r = ring_name ? atoi(ring_name) : ~0;
202 		r = (r < NETMAP_RING_MASK) ? (r | NETMAP_HW_RING) : 0;
203 		d->req.nr_ringid = r; /* set the ring */
204 	}
205 	d->req.nr_ringid |= (flags & ~NETMAP_RING_MASK);
206 	d->req.nr_version = NETMAP_API;
207 	strncpy(d->req.nr_name, ifname, sizeof(d->req.nr_name));
208 	if (ioctl(d->fd, NIOCREGIF, &d->req))
209 		goto fail;
210 
211 	d->memsize = d->req.nr_memsize;
212 	d->mem = mmap(0, d->memsize, PROT_WRITE | PROT_READ, MAP_SHARED,
213 			d->fd, 0);
214 	if (d->mem == NULL)
215 		goto fail;
216 	d->nifp = NETMAP_IF(d->mem, d->req.nr_offset);
217 	if (d->req.nr_ringid & NETMAP_SW_RING) {
218 		d->first_ring = d->last_ring = d->req.nr_rx_rings;
219 	} else if (d->req.nr_ringid & NETMAP_HW_RING) {
220 		d->first_ring = d->last_ring =
221 			d->req.nr_ringid & NETMAP_RING_MASK;
222 	} else {
223 		d->first_ring = 0;
224 		d->last_ring = d->req.nr_rx_rings - 1;
225 	}
226 	d->cur_ring = d->first_ring;
227 	for (n = d->first_ring; n <= d->last_ring; n++) {
228 		struct netmap_ring *ring = NETMAP_RXRING(d->nifp, n);
229 		ring->flags |= ring_flags;
230 	}
231 	return d;
232 
233 fail:
234 	nm_close(d);
235 	errno = EINVAL;
236 	return NULL;
237 }
238 
239 
240 static int
nm_close(struct nm_desc_t * d)241 nm_close(struct nm_desc_t *d)
242 {
243 	if (d == NULL || d->self != d)
244 		return EINVAL;
245 	if (d->mem)
246 		munmap(d->mem, d->memsize);
247 	if (d->fd)
248 		close(d->fd);
249 	bzero(d, sizeof(*d));
250 	free(d);
251 	return 0;
252 }
253 
254 
255 /*
256  * Same prototype as pcap_dispatch(), only need to cast.
257  */
258 inline /* not really, but disable unused warnings */
259 static int
nm_dispatch(struct nm_desc_t * d,int cnt,nm_cb_t cb,u_char * arg)260 nm_dispatch(struct nm_desc_t *d, int cnt, nm_cb_t cb, u_char *arg)
261 {
262 	int n = d->last_ring - d->first_ring + 1;
263 	int c, got = 0, ri = d->cur_ring;
264 
265 	if (cnt == 0)
266 		cnt = -1;
267 	/* cnt == -1 means infinite, but rings have a finite amount
268 	 * of buffers and the int is large enough that we never wrap,
269 	 * so we can omit checking for -1
270 	 */
271 	for (c=0; c < n && cnt != got; c++) {
272 		/* compute current ring to use */
273 		struct netmap_ring *ring;
274 
275 		ri = d->cur_ring + c;
276 		if (ri > d->last_ring)
277 			ri = d->first_ring;
278 		ring = NETMAP_RXRING(d->nifp, ri);
279 		for ( ; ring->avail > 0 && cnt != got; got++) {
280 			u_int i = ring->cur;
281 			u_int idx = ring->slot[i].buf_idx;
282 			u_char *buf = (u_char *)NETMAP_BUF(ring, idx);
283 			// XXX should check valid buf
284 			// prefetch(buf);
285 			d->hdr.len = d->hdr.caplen = ring->slot[i].len;
286 			d->hdr.ts = ring->ts;
287 			cb(arg, &d->hdr, buf);
288 			ring->cur = NETMAP_RING_NEXT(ring, i);
289 			ring->avail--;
290 		}
291 	}
292 	d->cur_ring = ri;
293 	return got;
294 }
295 
296 inline /* not really, but disable unused warnings */
297 static u_char *
nm_next(struct nm_desc_t * d,struct nm_hdr_t * hdr)298 nm_next(struct nm_desc_t *d, struct nm_hdr_t *hdr)
299 {
300 	int ri = d->cur_ring;
301 
302 	do {
303 		/* compute current ring to use */
304 		struct netmap_ring *ring = NETMAP_RXRING(d->nifp, ri);
305 		if (ring->avail > 0) {
306 			u_int i = ring->cur;
307 			u_int idx = ring->slot[i].buf_idx;
308 			u_char *buf = (u_char *)NETMAP_BUF(ring, idx);
309 			// XXX should check valid buf
310 			// prefetch(buf);
311 			hdr->ts = ring->ts;
312 			hdr->len = hdr->caplen = ring->slot[i].len;
313 			ring->cur = NETMAP_RING_NEXT(ring, i);
314 			ring->avail--;
315 			d->cur_ring = ri;
316 			return buf;
317 		}
318 		ri++;
319 		if (ri > d->last_ring)
320 			ri = d->first_ring;
321 	} while (ri != d->cur_ring);
322 	return NULL; /* nothing found */
323 }
324 
325 #endif /* !HAVE_NETMAP_WITH_LIBS */
326 
327 #endif /* NETMAP_WITH_LIBS */
328 
329 #endif /* _NET_NETMAP_USER_H_ */
330