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→Example: use source tag
Libsoccr is the library that does [[TCP connection]] checkpoint and restore. Currently it resides in criu source code (<code>soccr</code> subdirectory) and consists of an API header and a static library.
Libsoccr is a library that does [[TCP connection]] checkpoint and restore.
Libsoccr resides in criu source code (<code>soccr</code> subdirectory) and consists of an API header and a static library.
Libsoccr is available since CRIU {{criu|2.10}} release.
== Overview ==
== Overview ==
soccr/soccr.h declares three types:
soccr/soccr.h declares three types:
; <code>struct libsoccr_sk</code>
; <source lang="c" inline>struct libsoccr_sk</source>
: An abstract handler returned by ''pausing'' routine that is used as an opaque identifier by the rest of the libsoccr calls
: An abstract handler returned by ''pausing'' routine that is used as an opaque identifier by the rest of the libsoccr calls
; <code>struct libsoccr_sk_data</code>
; <source lang="c" inline>struct libsoccr_sk_data</source>
: A structure containing a set of 32-bit values that are returned by ''getter'' and that are to be passed '''as is''' to the ''setter'' call
: A structure containing a set of 32-bit values that are returned by ''getter'' and that are to be passed '''as is''' to the ''setter'' call
; <code>struct libsoccr_addr</code>
; <source lang="c" inline>struct libsoccr_addr</source>
: A structure that defines soccaddr for a socket. It's used by set/get calls described further.
: A structure that defines soccaddr for a socket. It's used by set/get calls described further.
Here are the flags that make sense:
Here are the flags that make sense:
; <code>SOCCR_FLAGS_WINDOW == 0x1</code>
; <source lang="c" inline>SOCCR_FLAGS_WINDOW == 0x1</source>
: When set, indicates that fields <code>snd_wl1</code>, <code>snd_wnd</code>, <code>max_window</code>, <code>rcv_wnd</code> and <code>rcv_wup</code> contain some valuable data (0 is a valid value for any of these)
: When set, indicates that fields <code>snd_wl1</code>, <code>snd_wnd</code>, <code>max_window</code>, <code>rcv_wnd</code> and <code>rcv_wup</code> contain some valuable data (0 is a valid value for any of these)
=== Generic ===
=== Generic ===
; <code>struct libsoccr_sk *libsoccr_pause(int sk)</code>
; <source lang="c" inline>struct libsoccr_sk *libsoccr_pause(int sk)</source>
: Pauses the socket and returns a handler for further operations. Any data flow for this socket ''must be blocked by the caller'' before this call.
: Pauses the socket and returns a handler for further operations. Any data flow for this socket ''must be blocked by the caller'' before this call.
; <code>void libsoccr_resume(struct libsoccr_sk *)</code>
; <source lang="c" inline>void libsoccr_resume(struct libsoccr_sk *)</source>
: Resumes the socket. Data flow unlock may happen before this.
: Resumes the socket and frees the handler. Data flow unlock may happen before this.
; <source lang="c" inline>void libsoccr_release(struct libsoccr_sk *)</source>
: Only releases the handler and doesn't do anything with the socket itself. Use when saving the state and willing to kill the socket -- call <code>close()</code> on descriptor and this thing on the handler.
; <code>void libsoccr_set_log(unsigned int level, void (*fn)(unsigned int level, const char *fmt, ...))</code>
; <source lang="c" inline>void libsoccr_set_log(unsigned int level, void (*fn)(unsigned int level, const char *fmt, ...))</source>
: Sets a function that will be called when libsoccr will want to print something on the screen.
: Sets a function that will be called when libsoccr will want to print something on the screen.
=== Dump ===
=== Dump ===
; <code>int libsoccr_save(struct libsoccr_sk *sk, struct libsoccr_sk_data *data, unsigned data_size)</code>
; <source lang="c" inline>int libsoccr_save(struct libsoccr_sk *sk, struct libsoccr_sk_data *data, unsigned data_size)</source>
: Fills in the <code>data</code> structure with the info get from paused socket. The <code>data_size</code> should be the size of the structure passed. The return code is the size of the structure really filled with data.
: Fills in the <code>data</code> structure with the info get from paused socket. The <code>data_size</code> should be the size of the structure passed. The return code is the size of the structure really filled with data.
; <code>char *libsoccr_get_queue_bytes(struct libsoccr_sk *sk, int queue_id, unsigned flags)</code>
; <source lang="c" inline>char *libsoccr_get_queue_bytes(struct libsoccr_sk *sk, int queue_id, unsigned flags)</source>
: Returns a malloc()-ed array with the contents of the queue. The queue can be TCP_RECV_QUEUE or TCP_SEND_QUEUE. The amount of bytes in each is <code>data.inq_len</code> and <code>data.outq_len</code> respectively. The <code>flags</code> may have <code>SOCCR_MEM_EXCL</code> bit set (see below).
: Returns a malloc()-ed array with the contents of the queue. The queue can be TCP_RECV_QUEUE or TCP_SEND_QUEUE. The amount of bytes in each is <code>data.inq_len</code> and <code>data.outq_len</code> respectively. The <code>flags</code> may have <code>SOCCR_MEM_EXCL</code> bit set (see below).
; <code>union libsoccr_addr *libsoccr_get_addr(struct libsoccr_sk *sk, int self, unsigned flags)</code> (currently unimplemented and returns NULL)
; <source lang="c" inline>union libsoccr_addr *libsoccr_get_addr(struct libsoccr_sk *sk, int self, unsigned flags)</source> (currently unimplemented and returns NULL)
: Returns address (self or peer) of the socket. The <code>flags</code> may have <code>SOCCR_MEM_EXCL</code> bit set (see below)
: Returns address (self or peer) of the socket. The <code>flags</code> may have <code>SOCCR_MEM_EXCL</code> bit set (see below)
=== Restore ===
=== Restore ===
; <code>int libsoccr_restore(struct libsoccr_sk *sk, struct libsoccr_sk_data *data, unsigned data_size)</code>
; <source lang="c" inline>int libsoccr_restore(struct libsoccr_sk *sk, struct libsoccr_sk_data *data, unsigned data_size)</source>
: Restores data on a socket from the <code>data</code> structure. Should be called after the calls below, but before the "resume" one.
: Restores data on a socket from the <code>data</code> structure. Should be called after the calls below, but before the "resume" one.
; <code>int libsoccr_set_queue_bytes(struct libsoccr_sk *sk, int queue, char *buf, unsigned flags)</code>
; <source lang="c" inline>int libsoccr_set_queue_bytes(struct libsoccr_sk *sk, int queue, char *buf, unsigned flags)</source>
: Puts back the contents of the respective queue. The <code>flags</code> may contain <code>SOCCR_MEM_EXCL</code>.
: Puts back the contents of the respective queue. The <code>flags</code> may contain <code>SOCCR_MEM_EXCL</code>.
; <code>int libsoccr_set_addr(struct libsoccr_sk *sk, int self, union libsoccr_addr *, unsigned flags)</code>
; <source lang="c" inline>int libsoccr_set_addr(struct libsoccr_sk *sk, int self, union libsoccr_addr *, unsigned flags)</source>
: Sets address (self or peer) of the socket. The <code>flags</code> may contain <code>SOCCR_MEM_EXCL</code>.
: Sets address (self or peer) of the socket. The <code>flags</code> may contain <code>SOCCR_MEM_EXCL</code>.
[[Category: Sub-projects]]
[[Category: Sub-projects]]
[[Category: Sockets]]
[[Category: Sockets]]
== Example ==
<source lang="c">
/* Dump a tcp socket */
dst_let = sizeof(addr);
if (getsockname(sock, (struct sockaddr *) &addr, &dst_let)) {
pr_perror("connect");
return -1;
}
dst_let = sizeof(addr);
if (getpeername(sock, (struct sockaddr *) &dst, &dst_let)) {
pr_perror("connect");
return -1;
}
so = libsoccr_pause(sock);
dsize = libsoccr_save(so, &data, sizeof(data));
if (dsize < 0) {
pr_perror("libsoccr_save");
return -1;
}
close(sock);
/* Restore a tcp socket */
rst = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (rst == -1)
return -1;
so_rst = libsoccr_pause(rst);
libsoccr_set_addr(so_rst, 1, &addr, 0);
libsoccr_set_addr(so_rst, 0, &dst, 0);
queue = libsoccr_get_queue_bytes(so, TCP_RECV_QUEUE, SOCCR_MEM_EXCL);
libsoccr_set_queue_bytes(so_rst, TCP_RECV_QUEUE, queue, SOCCR_MEM_EXCL);
queue = libsoccr_get_queue_bytes(so, TCP_SEND_QUEUE, SOCCR_MEM_EXCL);
libsoccr_set_queue_bytes(so_rst, TCP_SEND_QUEUE, queue, SOCCR_MEM_EXCL);
ret = libsoccr_restore(so_rst, &data, dsize);
if (ret)
return -1;
libsoccr_resume(so_rst);
libsoccr_resume(so);
</source>