1 /*
2  * vhost-user-scsi sample application
3  *
4  * Copyright (c) 2016 Nutanix Inc. All rights reserved.
5  *
6  * Author:
7  *  Felipe Franciosi <felipe@nutanix.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2 only.
10  * See the COPYING file in the top-level directory.
11  */
12 
13 #include "qemu/osdep.h"
14 #include <iscsi/iscsi.h>
15 #define inline __attribute__((gnu_inline))  /* required for libiscsi v1.9.0 */
16 #include <iscsi/scsi-lowlevel.h>
17 #undef inline
18 #include "contrib/libvhost-user/libvhost-user-glib.h"
19 #include "standard-headers/linux/virtio_scsi.h"
20 
21 
22 #define VUS_ISCSI_INITIATOR "iqn.2016-11.com.nutanix:vhost-user-scsi"
23 
24 enum {
25     VHOST_USER_SCSI_MAX_QUEUES = 8,
26 };
27 
28 typedef struct VusIscsiLun {
29     struct iscsi_context *iscsi_ctx;
30     int iscsi_lun;
31 } VusIscsiLun;
32 
33 typedef struct VusDev {
34     VugDev parent;
35 
36     VusIscsiLun lun;
37     GMainLoop *loop;
38 } VusDev;
39 
40 /** libiscsi integration **/
41 
42 typedef struct virtio_scsi_cmd_req VirtIOSCSICmdReq;
43 typedef struct virtio_scsi_cmd_resp VirtIOSCSICmdResp;
44 
45 static int vus_iscsi_add_lun(VusIscsiLun *lun, char *iscsi_uri)
46 {
47     struct iscsi_url *iscsi_url;
48     struct iscsi_context *iscsi_ctx;
49     int ret = 0;
50 
51     assert(lun);
52     assert(iscsi_uri);
53     assert(!lun->iscsi_ctx);
54 
55     iscsi_ctx = iscsi_create_context(VUS_ISCSI_INITIATOR);
56     if (!iscsi_ctx) {
57         g_warning("Unable to create iSCSI context");
58         return -1;
59     }
60 
61     iscsi_url = iscsi_parse_full_url(iscsi_ctx, iscsi_uri);
62     if (!iscsi_url) {
63         g_warning("Unable to parse iSCSI URL: %s", iscsi_get_error(iscsi_ctx));
64         goto fail;
65     }
66 
67     iscsi_set_session_type(iscsi_ctx, ISCSI_SESSION_NORMAL);
68     iscsi_set_header_digest(iscsi_ctx, ISCSI_HEADER_DIGEST_NONE_CRC32C);
69     if (iscsi_full_connect_sync(iscsi_ctx, iscsi_url->portal, iscsi_url->lun)) {
70         g_warning("Unable to login to iSCSI portal: %s",
71                   iscsi_get_error(iscsi_ctx));
72         goto fail;
73     }
74 
75     lun->iscsi_ctx = iscsi_ctx;
76     lun->iscsi_lun = iscsi_url->lun;
77 
78     g_debug("Context %p created for lun 0: %s", iscsi_ctx, iscsi_uri);
79 
80 out:
81     if (iscsi_url) {
82         iscsi_destroy_url(iscsi_url);
83     }
84     return ret;
85 
86 fail:
87     (void)iscsi_destroy_context(iscsi_ctx);
88     ret = -1;
89     goto out;
90 }
91 
92 static struct scsi_task *scsi_task_new(int cdb_len, uint8_t *cdb, int dir,
93                                        int xfer_len)
94 {
95     struct scsi_task *task;
96 
97     assert(cdb_len > 0);
98     assert(cdb);
99 
100     task = g_new0(struct scsi_task, 1);
101     memcpy(task->cdb, cdb, cdb_len);
102     task->cdb_size = cdb_len;
103     task->xfer_dir = dir;
104     task->expxferlen = xfer_len;
105 
106     return task;
107 }
108 
109 static int get_cdb_len(uint8_t *cdb)
110 {
111     assert(cdb);
112 
113     switch (cdb[0] >> 5) {
114     case 0: return 6;
115     case 1: /* fall through */
116     case 2: return 10;
117     case 4: return 16;
118     case 5: return 12;
119     }
120     g_warning("Unable to determine cdb len (0x%02hhX)", (uint8_t)(cdb[0] >> 5));
121     return -1;
122 }
123 
124 static int handle_cmd_sync(struct iscsi_context *ctx,
125                            VirtIOSCSICmdReq *req,
126                            struct iovec *out, unsigned int out_len,
127                            VirtIOSCSICmdResp *rsp,
128                            struct iovec *in, unsigned int in_len)
129 {
130     struct scsi_task *task;
131     uint32_t dir;
132     uint32_t len;
133     int cdb_len;
134     int i;
135 
136     assert(ctx);
137     assert(req);
138     assert(rsp);
139 
140     if (!(!req->lun[1] && req->lun[2] == 0x40 && !req->lun[3])) {
141         /* Ignore anything different than target=0, lun=0 */
142         g_debug("Ignoring unconnected lun (0x%hhX, 0x%hhX)",
143              req->lun[1], req->lun[3]);
144         rsp->status = SCSI_STATUS_CHECK_CONDITION;
145         memset(rsp->sense, 0, sizeof(rsp->sense));
146         rsp->sense_len = 18;
147         rsp->sense[0] = 0x70;
148         rsp->sense[2] = SCSI_SENSE_ILLEGAL_REQUEST;
149         rsp->sense[7] = 10;
150         rsp->sense[12] = 0x24;
151 
152         return 0;
153     }
154 
155     cdb_len = get_cdb_len(req->cdb);
156     if (cdb_len == -1) {
157         return -1;
158     }
159 
160     len = 0;
161     if (!out_len && !in_len) {
162         dir = SCSI_XFER_NONE;
163     } else if (out_len) {
164         dir = SCSI_XFER_WRITE;
165         for (i = 0; i < out_len; i++) {
166             len += out[i].iov_len;
167         }
168     } else {
169         dir = SCSI_XFER_READ;
170         for (i = 0; i < in_len; i++) {
171             len += in[i].iov_len;
172         }
173     }
174 
175     task = scsi_task_new(cdb_len, req->cdb, dir, len);
176 
177     if (dir == SCSI_XFER_WRITE) {
178         task->iovector_out.iov = (struct scsi_iovec *)out;
179         task->iovector_out.niov = out_len;
180     } else if (dir == SCSI_XFER_READ) {
181         task->iovector_in.iov = (struct scsi_iovec *)in;
182         task->iovector_in.niov = in_len;
183     }
184 
185     g_debug("Sending iscsi cmd (cdb_len=%d, dir=%d, task=%p)",
186          cdb_len, dir, task);
187     if (!iscsi_scsi_command_sync(ctx, 0, task, NULL)) {
188         g_warning("Error serving SCSI command");
189         g_free(task);
190         return -1;
191     }
192 
193     memset(rsp, 0, sizeof(*rsp));
194 
195     rsp->status = task->status;
196     rsp->resid  = task->residual;
197 
198     if (task->status == SCSI_STATUS_CHECK_CONDITION) {
199         rsp->response = VIRTIO_SCSI_S_FAILURE;
200         rsp->sense_len = task->datain.size - 2;
201         memcpy(rsp->sense, &task->datain.data[2], rsp->sense_len);
202     }
203 
204     g_free(task);
205 
206     g_debug("Filled in rsp: status=%hhX, resid=%u, response=%hhX, sense_len=%u",
207          rsp->status, rsp->resid, rsp->response, rsp->sense_len);
208 
209     return 0;
210 }
211 
212 /** libvhost-user callbacks **/
213 
214 static void vus_panic_cb(VuDev *vu_dev, const char *buf)
215 {
216     VugDev *gdev;
217     VusDev *vdev_scsi;
218 
219     assert(vu_dev);
220 
221     gdev = container_of(vu_dev, VugDev, parent);
222     vdev_scsi = container_of(gdev, VusDev, parent);
223     if (buf) {
224         g_warning("vu_panic: %s", buf);
225     }
226 
227     g_main_loop_quit(vdev_scsi->loop);
228 }
229 
230 static void vus_proc_req(VuDev *vu_dev, int idx)
231 {
232     VugDev *gdev;
233     VusDev *vdev_scsi;
234     VuVirtq *vq;
235     VuVirtqElement *elem = NULL;
236 
237     assert(vu_dev);
238 
239     gdev = container_of(vu_dev, VugDev, parent);
240     vdev_scsi = container_of(gdev, VusDev, parent);
241 
242     vq = vu_get_queue(vu_dev, idx);
243     if (!vq) {
244         g_warning("Error fetching VQ (dev=%p, idx=%d)", vu_dev, idx);
245         vus_panic_cb(vu_dev, NULL);
246         return;
247     }
248 
249     g_debug("Got kicked on vq[%d]@%p", idx, vq);
250 
251     while (1) {
252         VirtIOSCSICmdReq *req;
253         VirtIOSCSICmdResp *rsp;
254 
255         elem = vu_queue_pop(vu_dev, vq, sizeof(VuVirtqElement));
256         if (!elem) {
257             g_debug("No more elements pending on vq[%d]@%p", idx, vq);
258             break;
259         }
260         g_debug("Popped elem@%p", elem);
261 
262         assert(!(elem->out_num > 1 && elem->in_num > 1));
263         assert(elem->out_num > 0 && elem->in_num > 0);
264 
265         if (elem->out_sg[0].iov_len < sizeof(VirtIOSCSICmdReq)) {
266             g_warning("Invalid virtio-scsi req header");
267             vus_panic_cb(vu_dev, NULL);
268             break;
269         }
270         req = (VirtIOSCSICmdReq *)elem->out_sg[0].iov_base;
271 
272         if (elem->in_sg[0].iov_len < sizeof(VirtIOSCSICmdResp)) {
273             g_warning("Invalid virtio-scsi rsp header");
274             vus_panic_cb(vu_dev, NULL);
275             break;
276         }
277         rsp = (VirtIOSCSICmdResp *)elem->in_sg[0].iov_base;
278 
279         if (handle_cmd_sync(vdev_scsi->lun.iscsi_ctx,
280                             req, &elem->out_sg[1], elem->out_num - 1,
281                             rsp, &elem->in_sg[1], elem->in_num - 1) != 0) {
282             vus_panic_cb(vu_dev, NULL);
283             break;
284         }
285 
286         vu_queue_push(vu_dev, vq, elem, 0);
287         vu_queue_notify(vu_dev, vq);
288 
289         free(elem);
290     }
291     free(elem);
292 }
293 
294 static void vus_queue_set_started(VuDev *vu_dev, int idx, bool started)
295 {
296     VuVirtq *vq;
297 
298     assert(vu_dev);
299 
300     vq = vu_get_queue(vu_dev, idx);
301 
302     if (idx == 0 || idx == 1) {
303         g_debug("queue %d unimplemented", idx);
304     } else {
305         vu_set_queue_handler(vu_dev, vq, started ? vus_proc_req : NULL);
306     }
307 }
308 
309 static const VuDevIface vus_iface = {
310     .queue_set_started = vus_queue_set_started,
311 };
312 
313 /** misc helpers **/
314 
315 static int unix_sock_new(char *unix_fn)
316 {
317     int sock;
318     struct sockaddr_un un;
319     size_t len;
320 
321     assert(unix_fn);
322 
323     sock = socket(AF_UNIX, SOCK_STREAM, 0);
324     if (sock < 0) {
325         perror("socket");
326         return -1;
327     }
328 
329     un.sun_family = AF_UNIX;
330     (void)snprintf(un.sun_path, sizeof(un.sun_path), "%s", unix_fn);
331     len = sizeof(un.sun_family) + strlen(un.sun_path);
332 
333     (void)unlink(unix_fn);
334     if (bind(sock, (struct sockaddr *)&un, len) < 0) {
335         perror("bind");
336         goto fail;
337     }
338 
339     if (listen(sock, 1) < 0) {
340         perror("listen");
341         goto fail;
342     }
343 
344     return sock;
345 
346 fail:
347     (void)close(sock);
348 
349     return -1;
350 }
351 
352 /** vhost-user-scsi **/
353 
354 int main(int argc, char **argv)
355 {
356     VusDev *vdev_scsi = NULL;
357     char *unix_fn = NULL;
358     char *iscsi_uri = NULL;
359     int lsock = -1, csock = -1, opt, err = EXIT_SUCCESS;
360 
361     while ((opt = getopt(argc, argv, "u:i:")) != -1) {
362         switch (opt) {
363         case 'h':
364             goto help;
365         case 'u':
366             unix_fn = g_strdup(optarg);
367             break;
368         case 'i':
369             iscsi_uri = g_strdup(optarg);
370             break;
371         default:
372             goto help;
373         }
374     }
375     if (!unix_fn || !iscsi_uri) {
376         goto help;
377     }
378 
379     lsock = unix_sock_new(unix_fn);
380     if (lsock < 0) {
381         goto err;
382     }
383 
384     csock = accept(lsock, NULL, NULL);
385     if (csock < 0) {
386         perror("accept");
387         goto err;
388     }
389 
390     vdev_scsi = g_new0(VusDev, 1);
391     vdev_scsi->loop = g_main_loop_new(NULL, FALSE);
392 
393     if (vus_iscsi_add_lun(&vdev_scsi->lun, iscsi_uri) != 0) {
394         goto err;
395     }
396 
397     if (!vug_init(&vdev_scsi->parent, VHOST_USER_SCSI_MAX_QUEUES, csock,
398                   vus_panic_cb, &vus_iface)) {
399         g_printerr("Failed to initialize libvhost-user-glib\n");
400         goto err;
401     }
402 
403     g_main_loop_run(vdev_scsi->loop);
404 
405     vug_deinit(&vdev_scsi->parent);
406 
407 out:
408     if (vdev_scsi) {
409         g_main_loop_unref(vdev_scsi->loop);
410         g_free(vdev_scsi);
411         unlink(unix_fn);
412     }
413     if (csock >= 0) {
414         close(csock);
415     }
416     if (lsock >= 0) {
417         close(lsock);
418     }
419     g_free(unix_fn);
420     g_free(iscsi_uri);
421 
422     return err;
423 
424 err:
425     err = EXIT_FAILURE;
426     goto out;
427 
428 help:
429     fprintf(stderr, "Usage: %s [ -u unix_sock_path -i iscsi_uri ] | [ -h ]\n",
430             argv[0]);
431     fprintf(stderr, "          -u path to unix socket\n");
432     fprintf(stderr, "          -i iscsi uri for lun 0\n");
433     fprintf(stderr, "          -h print help and quit\n");
434 
435     goto err;
436 }
437