2 * Copyright (C) 2011 Matteo Landi, Luigi Rizzo. All rights reserved.
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5 * modification, are permitted provided that the following conditions are
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9 * notice, this list of conditions and the following disclaimer.
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20 * THIS SOFTWARE IS PROVIDED BY MATTEO LANDI AND CONTRIBUTORS "AS IS" AND
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35 * $Id: netmap.h 11997 2013-01-17 21:59:12Z luigi $
37 * Definitions of constants and the structures used by the netmap
38 * framework, for the part visible to both kernel and userspace.
39 * Detailed info on netmap is available with "man netmap" or at
41 * http://info.iet.unipi.it/~luigi/netmap/
44 #ifndef _NET_NETMAP_H_
45 #define _NET_NETMAP_H_
48 * --- Netmap data structures ---
50 * The data structures used by netmap are shown below. Those in
51 * capital letters are in an mmapp()ed area shared with userspace,
52 * while others are private to the kernel.
53 * Shared structures do not contain pointers but only memory
54 * offsets, so that addressing is portable between kernel and userspace.
60 | if_pspare[0] ----------+
63 +----------------+<------+
66 | tx_rings *--------------------------------->+---------------+
67 | | netmap_kring | ring *---------.
68 | rx_rings *--------->+---------------+ | nr_hwcur | |
69 +----------------+ | ring *--------. | nr_hwavail | V
70 | nr_hwcur | | | selinfo | |
71 | nr_hwavail | | +---------------+ .
72 | selinfo | | | ... | .
73 +---------------+ | |(ntx+1 entries)|
75 |(nrx+1 entries)| | +---------------+
77 KERNEL +---------------+ |
79 ====================================================================
81 USERSPACE | NETMAP_RING
84 NETMAP_IF (nifp, one per file desc.) / | avail |
85 +---------------+ / | buf_ofs |
86 | ni_tx_rings | / +=============+
87 | ni_rx_rings | / | buf_idx | slot[0]
90 +===============+ / | buf_idx | slot[1]
91 | txring_ofs[0] | (rel.to nifp)--' | len, flags |
92 | txring_ofs[1] | +-------------+
93 (num_rings+1 entries) (nr_num_slots entries)
94 | txring_ofs[n] | | buf_idx | slot[n-1]
95 +---------------+ | len, flags |
96 | rxring_ofs[0] | +-------------+
102 * The private descriptor ('softc' or 'adapter') of each interface
103 * is extended with a "struct netmap_adapter" containing netmap-related
104 * info (see description in dev/netmap/netmap_kernel.h.
105 * Among other things, tx_rings and rx_rings point to the arrays of
106 * "struct netmap_kring" which in turn reache the various
107 * "struct netmap_ring", shared with userspace.
109 * The NETMAP_RING is the userspace-visible replica of the NIC ring.
110 * Each slot has the index of a buffer, its length and some flags.
111 * In user space, the buffer address is computed as
112 * (char *)ring + buf_ofs + index*NETMAP_BUF_SIZE
113 * In the kernel, buffers do not necessarily need to be contiguous,
114 * and the virtual and physical addresses are derived through
117 * struct netmap_slot:
119 * buf_idx is the index of the buffer associated to the slot.
120 * len is the length of the payload
121 * NS_BUF_CHANGED must be set whenever userspace wants
122 * to change buf_idx (it might be necessary to
123 * reprogram the NIC slot)
124 * NS_REPORT must be set if we want the NIC to generate an interrupt
125 * when this slot is used. Leaving it to 0 improves
127 * NS_FORWARD if set on a receive ring, and the device is in
128 * transparent mode, buffers released with the flag set
129 * will be forwarded to the 'other' side (host stack
130 * or NIC, respectively) on the next select() or ioctl()
131 * NS_NO_LEARN on a VALE switch, do not 'learn' the source port for
133 * NS_PORT_MASK the high 8 bits of the flag, if not zero, indicate the
134 * destination port for the VALE switch, overriding
139 uint32_t buf_idx; /* buffer index */
140 uint16_t len; /* packet length, to be copied to/from the hw ring */
141 uint16_t flags; /* buf changed, etc. */
142 #define NS_BUF_CHANGED 0x0001 /* must resync the map, buffer changed */
143 #define NS_REPORT 0x0002 /* ask the hardware to report results
144 * e.g. by generating an interrupt
146 #define NS_FORWARD 0x0004 /* pass packet to the other endpoint
147 * (host stack or device)
149 #define NS_NO_LEARN 0x0008
150 #define NS_PORT_SHIFT 8
151 #define NS_PORT_MASK (0xff << NS_PORT_SHIFT)
155 * Netmap representation of a TX or RX ring (also known as "queue").
156 * This is a queue implemented as a fixed-size circular array.
157 * At the software level, two fields are important: avail and cur.
160 * avail indicates the number of slots available for transmission.
161 * It is updated by the kernel after every netmap system call.
162 * It MUST BE decremented by the application when it appends a
164 * cur indicates the slot to use for the next packet
165 * to send (i.e. the "tail" of the queue).
166 * It MUST BE incremented by the application before
167 * netmap system calls to reflect the number of newly
169 * It is checked by the kernel on netmap system calls
170 * (normally unmodified by the kernel unless invalid).
172 * The kernel side of netmap uses two additional fields in its own
173 * private ring structure, netmap_kring:
174 * nr_hwcur is a copy of nr_cur on an NIOCTXSYNC.
175 * nr_hwavail is the number of slots known as available by the
176 * hardware. It is updated on an INTR (inc by the
177 * number of packets sent) and on a NIOCTXSYNC
178 * (decrease by nr_cur - nr_hwcur)
179 * A special case, nr_hwavail is -1 if the transmit
180 * side is idle (no pending transmits).
183 * avail is the number of packets available (possibly 0).
184 * It MUST BE decremented by the application when it consumes
185 * a packet, and it is updated to nr_hwavail on a NIOCRXSYNC
186 * cur indicates the first slot that contains a packet not
187 * processed yet (the "head" of the queue).
188 * It MUST BE incremented by the software when it consumes
190 * reserved indicates the number of buffers before 'cur'
191 * that the application has still in use. Normally 0,
192 * it MUST BE incremented by the application when it
193 * does not return the buffer immediately, and decremented
194 * when the buffer is finally freed.
196 * The kernel side of netmap uses two additional fields in the kring:
197 * nr_hwcur is a copy of nr_cur on an NIOCRXSYNC
198 * nr_hwavail is the number of packets available. It is updated
199 * on INTR (inc by the number of new packets arrived)
200 * and on NIOCRXSYNC (decreased by nr_cur - nr_hwcur).
202 * DATA OWNERSHIP/LOCKING:
203 * The netmap_ring is owned by the user program and it is only
204 * accessed or modified in the upper half of the kernel during
207 * The netmap_kring is only modified by the upper half of the kernel.
210 * NR_TIMESTAMP updates the 'ts' field on each syscall. This is
211 * a global timestamp for all packets.
212 * NR_RX_TSTMP if set, the last 64 byte in each buffer will
213 * contain a timestamp for the frame supplied by
214 * the hardware (if supported)
215 * NR_FORWARD if set, the NS_FORWARD flag in each slot of the
216 * RX ring is checked, and if set the packet is
217 * passed to the other side (host stack or device,
218 * respectively). This permits bpf-like behaviour
219 * or transparency for selected packets.
223 * nr_buf_base_ofs is meant to be used through macros.
224 * It contains the offset of the buffer region from this
227 const ssize_t buf_ofs;
228 const uint32_t num_slots; /* number of slots in the ring. */
229 uint32_t avail; /* number of usable slots */
230 uint32_t cur; /* 'current' r/w position */
231 uint32_t reserved; /* not refilled before current */
233 const uint16_t nr_buf_size;
235 #define NR_TIMESTAMP 0x0002 /* set timestamp on *sync() */
236 #define NR_FORWARD 0x0004 /* enable NS_FORWARD for ring */
237 #define NR_RX_TSTMP 0x0008 /* set rx timestamp in slots */
239 struct timeval ts; /* time of last *sync() */
241 /* the slots follow. This struct has variable size */
242 struct netmap_slot slot[0]; /* array of slots. */
247 * Netmap representation of an interface and its queue(s).
248 * There is one netmap_if for each file descriptor on which we want
249 * to select/poll. We assume that on each interface has the same number
250 * of receive and transmit queues.
251 * select/poll operates on one or all pairs depending on the value of
252 * nmr_queueid passed on the ioctl.
255 char ni_name[IFNAMSIZ]; /* name of the interface. */
256 const u_int ni_version; /* API version, currently unused */
257 const u_int ni_rx_rings; /* number of rx rings */
258 const u_int ni_tx_rings; /* if zero, same as ni_rx_rings */
260 * The following array contains the offset of each netmap ring
261 * from this structure. The first ni_tx_queues+1 entries refer
262 * to the tx rings, the next ni_rx_queues+1 refer to the rx rings
263 * (the last entry in each block refers to the host stack rings).
264 * The area is filled up by the kernel on NIOCREG,
265 * and then only read by userspace code.
267 const ssize_t ring_ofs[0];
272 * ioctl names and related fields
274 * NIOCGINFO takes a struct ifreq, the interface name is the input,
275 * the outputs are number of queues and number of descriptor
276 * for each queue (useful to set number of threads etc.).
278 * NIOCREGIF takes an interface name within a struct ifreq,
279 * and activates netmap mode on the interface (if possible).
281 * NIOCUNREGIF unregisters the interface associated to the fd.
283 * NIOCTXSYNC, NIOCRXSYNC synchronize tx or rx queues,
284 * whose identity is set in NIOCREGIF through nr_ringid
288 * struct nmreq overlays a struct ifreq
291 char nr_name[IFNAMSIZ];
292 uint32_t nr_version; /* API version */
293 #define NETMAP_API 3 /* current version */
294 uint32_t nr_offset; /* nifp offset in the shared region */
295 uint32_t nr_memsize; /* size of the shared region */
296 uint32_t nr_tx_slots; /* slots in tx rings */
297 uint32_t nr_rx_slots; /* slots in rx rings */
298 uint16_t nr_tx_rings; /* number of tx rings */
299 uint16_t nr_rx_rings; /* number of rx rings */
300 uint16_t nr_ringid; /* ring(s) we care about */
301 #define NETMAP_HW_RING 0x4000 /* low bits indicate one hw ring */
302 #define NETMAP_SW_RING 0x2000 /* process the sw ring */
303 #define NETMAP_NO_TX_POLL 0x1000 /* no automatic txsync on poll */
304 #define NETMAP_RING_MASK 0xfff /* the ring number */
310 * FreeBSD uses the size value embedded in the _IOWR to determine
311 * how much to copy in/out. So we need it to match the actual
312 * data structure we pass. We put some spares in the structure
313 * to ease compatibility with other versions
315 #define NIOCGINFO _IOWR('i', 145, struct nmreq) /* return IF info */
316 #define NIOCREGIF _IOWR('i', 146, struct nmreq) /* interface register */
317 #define NIOCUNREGIF _IO('i', 147) /* interface unregister */
318 #define NIOCTXSYNC _IO('i', 148) /* sync tx queues */
319 #define NIOCRXSYNC _IO('i', 149) /* sync rx queues */
320 #endif /* !NIOCREGIF */
322 #endif /* _NET_NETMAP_H_ */