[Qemu-devel] [PATCH 02/14] ./block/iscsi/socket.c

[ronniesahlberg]

From: Ronnie Sahlberg <address@hidden>

iscsi  client library  : socket.c
This file contains functions for basic manipulation of the socket
used to talk to a iscsi target.
This includes, connect, disconnect, basic primitives for interfacing
with an external eventsystem, reading and writing to the socket.

The socket layer is fully nonblocking and will read/write data based
on when the socket becomes readable/writeable through the eventsystem.

...

./block/iscsi/ contains a copy of a general purpose iscsi client
library which is aimed at providing a clientside api for iscsi
for both qemu/kvm as well as otther scsi related utilities.

As such, there is need to make merging across various consumers,
qemu/kvm being one of many here, as easy as possible when features
are added to the library.
As such, no consumer/qemu specific code is used in this library as well
as coding guidelined might not be adhered to 100%

It is the intention that this library will be useful for many
and that iscsi use spawned from this will flourish.

Signed-off-by: Ronnie Sahlberg <address@hidden>
---
 block/iscsi/socket.c |  344 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 344 insertions(+), 0 deletions(-)
 create mode 100644 block/iscsi/socket.c

diff --git a/block/iscsi/socket.c b/block/iscsi/socket.c
new file mode 100644
index 0000000..072668f
--- /dev/null
+++ b/block/iscsi/socket.c
@@ -0,0 +1,344 @@
+/*
+   Copyright (C) 2010 by Ronnie Sahlberg <address@hidden>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <netinet/in.h>
+#include <poll.h>
+#include <sys/ioctl.h>
+#include <arpa/inet.h>
+#include "iscsi.h"
+#include "iscsi-private.h"
+#include "slist.h"
+
+static void set_nonblocking(int fd)
+{
+       unsigned v;
+       v = fcntl(fd, F_GETFL, 0);
+       fcntl(fd, F_SETFL, v | O_NONBLOCK);
+}
+
+int
+iscsi_connect_async(struct iscsi_context *iscsi, const char *portal,
+                   iscsi_command_cb cb, void *private_data)
+{
+       int tpgt = -1;
+       int port = 3260;
+       char *str;
+       char *addr;
+       struct sockaddr_storage s;
+       struct sockaddr_in *sin = (struct sockaddr_in *)&s;
+       int socksize;
+
+       if (iscsi->fd != -1) {
+               iscsi_set_error(iscsi,
+                               "Trying to connect but already connected.");
+               return -1;
+       }
+
+       addr = strdup(portal);
+       if (addr == NULL) {
+               iscsi_set_error(iscsi, "Out-of-memory: "
+                               "Failed to strdup portal address.");
+               return -2;
+       }
+
+       /* check if we have a target portal group tag */
+       str = rindex(addr, ',');
+       if (str != NULL) {
+               tpgt = atoi(str+1);
+               str[0] = 0;
+       }
+
+       /* XXX need handling for {ipv6 addresses} */
+       /* for now, assume all is ipv4 */
+       str = rindex(addr, ':');
+       if (str != NULL) {
+               port = atoi(str+1);
+               str[0] = 0;
+       }
+
+       sin->sin_family = AF_INET;
+       sin->sin_port   = htons(port);
+       if (inet_pton(AF_INET, addr, &sin->sin_addr) != 1) {
+               iscsi_set_error(iscsi, "Invalid target:%s  "
+                               "Failed to convert to ip address.", addr);
+               free(addr);
+               return -3;
+       }
+       free(addr);
+
+       switch (s.ss_family) {
+       case AF_INET:
+               iscsi->fd = socket(AF_INET, SOCK_STREAM, 0);
+               socksize = sizeof(struct sockaddr_in);
+               break;
+       default:
+               iscsi_set_error(iscsi, "Unknown address family :%d. "
+                               "Only IPv4 supported so far.", s.ss_family);
+               return -4;
+
+       }
+
+       if (iscsi->fd == -1) {
+               iscsi_set_error(iscsi, "Failed to open iscsi socket. "
+                               "Errno:%s(%d).", strerror(errno), errno);
+               return -5;
+
+       }
+
+       iscsi->connect_cb  = cb;
+       iscsi->connect_data = private_data;
+
+       set_nonblocking(iscsi->fd);
+
+       if (connect(iscsi->fd, (struct sockaddr *)&s, socksize) != 0
+           && errno != EINPROGRESS) {
+               iscsi_set_error(iscsi, "Connect failed with errno : "
+                               "%s(%d)\n", strerror(errno), errno);
+               return -6;
+       }
+
+       return 0;
+}
+
+int
+iscsi_disconnect(struct iscsi_context *iscsi)
+{
+       if (iscsi->fd == -1) {
+               iscsi_set_error(iscsi, "Trying to disconnect "
+                               "but not connected");
+               return -1;
+       }
+
+       close(iscsi->fd);
+       iscsi->fd  = -1;
+       iscsi->is_connected = 0;
+
+       return 0;
+}
+
+int
+iscsi_get_fd(struct iscsi_context *iscsi)
+{
+       return iscsi->fd;
+}
+
+int
+iscsi_which_events(struct iscsi_context *iscsi)
+{
+       int events = POLLIN;
+
+       if (iscsi->is_connected == 0) {
+               events |= POLLOUT;
+       }
+
+       if (iscsi->outqueue) {
+               events |= POLLOUT;
+       }
+       return events;
+}
+
+static int
+iscsi_read_from_socket(struct iscsi_context *iscsi)
+{
+       int available;
+       int size;
+       unsigned char *buf;
+       ssize_t count;
+
+       if (ioctl(iscsi->fd, FIONREAD, &available) != 0) {
+               iscsi_set_error(iscsi, "ioctl FIONREAD returned error : "
+                               "%d\n", errno);
+               return -1;
+       }
+       if (available == 0) {
+               iscsi_set_error(iscsi, "no data readable in socket, "
+                               "socket is closed\n");
+               return -2;
+       }
+       size = iscsi->insize - iscsi->inpos + available;
+       buf = malloc(size);
+       if (buf == NULL) {
+               iscsi_set_error(iscsi, "failed to allocate %d bytes for "
+                               "input buffer\n", size);
+               return -3;
+       }
+       if (iscsi->insize > iscsi->inpos) {
+               memcpy(buf, iscsi->inbuf + iscsi->inpos,
+                      iscsi->insize - iscsi->inpos);
+               iscsi->insize -= iscsi->inpos;
+               iscsi->inpos   = 0;
+       }
+
+       count = read(iscsi->fd, buf + iscsi->insize, available);
+       if (count == -1) {
+               if (errno == EINTR) {
+                       free(buf);
+                       buf = NULL;
+                       return 0;
+               }
+               iscsi_set_error(iscsi, "read from socket failed, "
+                               "errno:%d\n", errno);
+               free(buf);
+               buf = NULL;
+               return -4;
+       }
+
+       if (iscsi->inbuf != NULL) {
+               free(iscsi->inbuf);
+       }
+       iscsi->inbuf   = buf;
+       iscsi->insize += count;
+
+       while (1) {
+               if (iscsi->insize - iscsi->inpos < 48) {
+                       return 0;
+               }
+               count = iscsi_get_pdu_size(iscsi,
+                                          iscsi->inbuf + iscsi->inpos);
+               if (iscsi->insize + iscsi->inpos < count) {
+                       return 0;
+               }
+               if (iscsi_process_pdu(iscsi, iscsi->inbuf + iscsi->inpos,
+                                     count) != 0) {
+                       free(buf);
+                       return -7;
+               }
+               iscsi->inpos += count;
+               if (iscsi->inpos == iscsi->insize) {
+                       free(iscsi->inbuf);
+                       iscsi->inbuf = NULL;
+                       iscsi->insize = 0;
+                       iscsi->inpos = 0;
+               }
+               if (iscsi->inpos > iscsi->insize) {
+                       iscsi_set_error(iscsi, "inpos > insize. bug!\n");
+                       return -6;
+               }
+       }
+
+       return 0;
+}
+
+static int
+iscsi_write_to_socket(struct iscsi_context *iscsi)
+{
+       ssize_t count;
+
+       if (iscsi->fd == -1) {
+               iscsi_set_error(iscsi, "trying to write but not connected\n");
+               return -2;
+       }
+
+       while (iscsi->outqueue != NULL) {
+               ssize_t total;
+
+               total = iscsi->outqueue->outdata.size;
+               total = (total + 3) & 0xfffffffc;
+
+               count = write(iscsi->fd,
+                             iscsi->outqueue->outdata.data
+                             + iscsi->outqueue->written,
+                             total - iscsi->outqueue->written);
+               if (count == -1) {
+                       if (errno == EAGAIN || errno == EWOULDBLOCK) {
+                               return 0;
+                       }
+                       iscsi_set_error(iscsi, "Error when writing to "
+                                       "socket :%d\n", errno);
+                       return -3;
+               }
+
+               iscsi->outqueue->written += count;
+               if (iscsi->outqueue->written == total) {
+                       struct iscsi_pdu *pdu = iscsi->outqueue;
+
+                       SLIST_REMOVE(&iscsi->outqueue, pdu);
+                       SLIST_ADD_END(&iscsi->waitpdu, pdu);
+               }
+       }
+       return 0;
+}
+
+int
+iscsi_service(struct iscsi_context *iscsi, int revents)
+{
+       if (revents & POLLERR) {
+               iscsi_set_error(iscsi, "iscsi_service: POLLERR, "
+                               "socket error.");
+               iscsi->connect_cb(iscsi, SCSI_STATUS_ERROR, NULL,
+                                 iscsi->connect_data);
+               return -1;
+       }
+       if (revents & POLLHUP) {
+               iscsi_set_error(iscsi, "iscsi_service: POLLHUP, "
+                               "socket error.");
+               iscsi->connect_cb(iscsi, SCSI_STATUS_ERROR, NULL,
+                                 iscsi->connect_data);
+               return -2;
+       }
+
+       if (iscsi->is_connected == 0 && iscsi->fd != -1 && revents&POLLOUT) {
+               iscsi->is_connected = 1;
+               iscsi->connect_cb(iscsi, SCSI_STATUS_GOOD, NULL,
+                                 iscsi->connect_data);
+               return 0;
+       }
+
+       if (revents & POLLOUT && iscsi->outqueue != NULL) {
+               if (iscsi_write_to_socket(iscsi) != 0) {
+                       return -3;
+               }
+       }
+       if (revents & POLLIN) {
+               if (iscsi_read_from_socket(iscsi) != 0)
+                       return -4;
+       }
+
+       return 0;
+}
+
+int
+iscsi_queue_pdu(struct iscsi_context *iscsi, struct iscsi_pdu *pdu)
+{
+       if (pdu == NULL) {
+               iscsi_set_error(iscsi, "trying to queue NULL pdu");
+               return -2;
+       }
+
+       if (iscsi->header_digest != ISCSI_HEADER_DIGEST_NONE) {
+               unsigned long crc;
+
+               crc = crc32c((char *)pdu->outdata.data, ISCSI_RAW_HEADER_SIZE);
+
+               pdu->outdata.data[ISCSI_RAW_HEADER_SIZE+3] = (crc >> 24)&0xff;
+               pdu->outdata.data[ISCSI_RAW_HEADER_SIZE+2] = (crc >> 16)&0xff;
+               pdu->outdata.data[ISCSI_RAW_HEADER_SIZE+1] = (crc >>  8)&0xff;
+               pdu->outdata.data[ISCSI_RAW_HEADER_SIZE+0] = (crc)      &0xff;
+       }
+
+       SLIST_ADD_END(&iscsi->outqueue, pdu);
+
+       return 0;
+}
+
-- 
1.7.3.1