nexmon – Rev 1
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/*
* lib/handlers.c default netlink message handlers
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation version 2.1
* of the License.
*
* Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
*/
/**
* @ingroup core
* @defgroup cb Callbacks/Customization
*
* @details
* @par 1) Setting up a callback set
* @code
* // Allocate a callback set and initialize it to the verbose default set
* struct nl_cb *cb = nl_cb_alloc(NL_CB_VERBOSE);
*
* // Modify the set to call my_func() for all valid messages
* nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, my_func, NULL);
*
* // Set the error message handler to the verbose default implementation
* // and direct it to print all errors to the given file descriptor.
* FILE *file = fopen(...);
* nl_cb_err(cb, NL_CB_VERBOSE, NULL, file);
* @endcode
* @{
*/
#include <netlink-local.h>
#include <netlink/netlink.h>
#include <netlink/utils.h>
#include <netlink/msg.h>
#include <netlink/handlers.h>
static void print_header_content(FILE *ofd, struct nlmsghdr *n)
{
char flags[128];
char type[32];
fprintf(ofd, "type=%s length=%u flags=<%s> sequence-nr=%u pid=%u",
nl_nlmsgtype2str(n->nlmsg_type, type, sizeof(type)),
n->nlmsg_len, nl_nlmsg_flags2str(n->nlmsg_flags, flags,
sizeof(flags)), n->nlmsg_seq, n->nlmsg_pid);
}
static int nl_valid_handler_verbose(struct nl_msg *msg, void *arg)
{
FILE *ofd = arg ? arg : stdout;
fprintf(ofd, "-- Warning: unhandled valid message: ");
print_header_content(ofd, nlmsg_hdr(msg));
fprintf(ofd, "\n");
return NL_OK;
}
static int nl_invalid_handler_verbose(struct nl_msg *msg, void *arg)
{
FILE *ofd = arg ? arg : stderr;
fprintf(ofd, "-- Error: Invalid message: ");
print_header_content(ofd, nlmsg_hdr(msg));
fprintf(ofd, "\n");
return NL_STOP;
}
static int nl_overrun_handler_verbose(struct nl_msg *msg, void *arg)
{
FILE *ofd = arg ? arg : stderr;
fprintf(ofd, "-- Error: Netlink Overrun: ");
print_header_content(ofd, nlmsg_hdr(msg));
fprintf(ofd, "\n");
return NL_STOP;
}
static int nl_error_handler_verbose(struct sockaddr_nl *who,
struct nlmsgerr *e, void *arg)
{
FILE *ofd = arg ? arg : stderr;
fprintf(ofd, "-- Error received: %s\n-- Original message: ",
strerror(-e->error));
print_header_content(ofd, &e->msg);
fprintf(ofd, "\n");
return -nl_syserr2nlerr(e->error);
}
static int nl_valid_handler_debug(struct nl_msg *msg, void *arg)
{
FILE *ofd = arg ? arg : stderr;
fprintf(ofd, "-- Debug: Unhandled Valid message: ");
print_header_content(ofd, nlmsg_hdr(msg));
fprintf(ofd, "\n");
return NL_OK;
}
static int nl_finish_handler_debug(struct nl_msg *msg, void *arg)
{
FILE *ofd = arg ? arg : stderr;
fprintf(ofd, "-- Debug: End of multipart message block: ");
print_header_content(ofd, nlmsg_hdr(msg));
fprintf(ofd, "\n");
return NL_STOP;
}
static int nl_msg_in_handler_debug(struct nl_msg *msg, void *arg)
{
FILE *ofd = arg ? arg : stderr;
fprintf(ofd, "-- Debug: Received Message:\n");
nl_msg_dump(msg, ofd);
return NL_OK;
}
static int nl_msg_out_handler_debug(struct nl_msg *msg, void *arg)
{
FILE *ofd = arg ? arg : stderr;
fprintf(ofd, "-- Debug: Sent Message:\n");
nl_msg_dump(msg, ofd);
return NL_OK;
}
static int nl_skipped_handler_debug(struct nl_msg *msg, void *arg)
{
FILE *ofd = arg ? arg : stderr;
fprintf(ofd, "-- Debug: Skipped message: ");
print_header_content(ofd, nlmsg_hdr(msg));
fprintf(ofd, "\n");
return NL_SKIP;
}
static int nl_ack_handler_debug(struct nl_msg *msg, void *arg)
{
FILE *ofd = arg ? arg : stderr;
fprintf(ofd, "-- Debug: ACK: ");
print_header_content(ofd, nlmsg_hdr(msg));
fprintf(ofd, "\n");
return NL_STOP;
}
static nl_recvmsg_msg_cb_t cb_def[NL_CB_TYPE_MAX+1][NL_CB_KIND_MAX+1] = {
[NL_CB_VALID] = {
[NL_CB_VERBOSE] = nl_valid_handler_verbose,
[NL_CB_DEBUG] = nl_valid_handler_debug,
},
[NL_CB_FINISH] = {
[NL_CB_DEBUG] = nl_finish_handler_debug,
},
[NL_CB_INVALID] = {
[NL_CB_VERBOSE] = nl_invalid_handler_verbose,
[NL_CB_DEBUG] = nl_invalid_handler_verbose,
},
[NL_CB_MSG_IN] = {
[NL_CB_DEBUG] = nl_msg_in_handler_debug,
},
[NL_CB_MSG_OUT] = {
[NL_CB_DEBUG] = nl_msg_out_handler_debug,
},
[NL_CB_OVERRUN] = {
[NL_CB_VERBOSE] = nl_overrun_handler_verbose,
[NL_CB_DEBUG] = nl_overrun_handler_verbose,
},
[NL_CB_SKIPPED] = {
[NL_CB_DEBUG] = nl_skipped_handler_debug,
},
[NL_CB_ACK] = {
[NL_CB_DEBUG] = nl_ack_handler_debug,
},
};
static nl_recvmsg_err_cb_t cb_err_def[NL_CB_KIND_MAX+1] = {
[NL_CB_VERBOSE] = nl_error_handler_verbose,
[NL_CB_DEBUG] = nl_error_handler_verbose,
};
/**
* @name Callback Handle Management
* @{
*/
/**
* Allocate a new callback handle
* @arg kind callback kind to be used for initialization
* @return Newly allocated callback handle or NULL
*/
struct nl_cb *nl_cb_alloc(enum nl_cb_kind kind)
{
int i;
struct nl_cb *cb;
if (kind < 0 || kind > NL_CB_KIND_MAX)
return NULL;
cb = calloc(1, sizeof(*cb));
if (!cb)
return NULL;
cb->cb_refcnt = 1;
for (i = 0; i <= NL_CB_TYPE_MAX; i++)
nl_cb_set(cb, i, kind, NULL, NULL);
nl_cb_err(cb, kind, NULL, NULL);
return cb;
}
/**
* Clone an existing callback handle
* @arg orig original callback handle
* @return Newly allocated callback handle being a duplicate of
* orig or NULL
*/
struct nl_cb *nl_cb_clone(struct nl_cb *orig)
{
struct nl_cb *cb;
cb = nl_cb_alloc(NL_CB_DEFAULT);
if (!cb)
return NULL;
memcpy(cb, orig, sizeof(*orig));
cb->cb_refcnt = 1;
return cb;
}
struct nl_cb *nl_cb_get(struct nl_cb *cb)
{
cb->cb_refcnt++;
return cb;
}
void nl_cb_put(struct nl_cb *cb)
{
if (!cb)
return;
cb->cb_refcnt--;
if (cb->cb_refcnt < 0)
BUG();
if (cb->cb_refcnt <= 0)
free(cb);
}
/** @} */
/**
* @name Callback Setup
* @{
*/
/**
* Set up a callback
* @arg cb callback set
* @arg type callback to modify
* @arg kind kind of implementation
* @arg func callback function (NL_CB_CUSTOM)
* @arg arg argument passed to callback
*
* @return 0 on success or a negative error code
*/
int nl_cb_set(struct nl_cb *cb, enum nl_cb_type type, enum nl_cb_kind kind,
nl_recvmsg_msg_cb_t func, void *arg)
{
if (type < 0 || type > NL_CB_TYPE_MAX)
return -NLE_RANGE;
if (kind < 0 || kind > NL_CB_KIND_MAX)
return -NLE_RANGE;
if (kind == NL_CB_CUSTOM) {
cb->cb_set[type] = func;
cb->cb_args[type] = arg;
} else {
cb->cb_set[type] = cb_def[type][kind];
cb->cb_args[type] = arg;
}
return 0;
}
/**
* Set up a all callbacks
* @arg cb callback set
* @arg kind kind of callback
* @arg func callback function
* @arg arg argument to be passwd to callback function
*
* @return 0 on success or a negative error code
*/
int nl_cb_set_all(struct nl_cb *cb, enum nl_cb_kind kind,
nl_recvmsg_msg_cb_t func, void *arg)
{
int i, err;
for (i = 0; i <= NL_CB_TYPE_MAX; i++) {
err = nl_cb_set(cb, i, kind, func, arg);
if (err < 0)
return err;
}
return 0;
}
/**
* Set up an error callback
* @arg cb callback set
* @arg kind kind of callback
* @arg func callback function
* @arg arg argument to be passed to callback function
*/
int nl_cb_err(struct nl_cb *cb, enum nl_cb_kind kind,
nl_recvmsg_err_cb_t func, void *arg)
{
if (kind < 0 || kind > NL_CB_KIND_MAX)
return -NLE_RANGE;
if (kind == NL_CB_CUSTOM) {
cb->cb_err = func;
cb->cb_err_arg = arg;
} else {
cb->cb_err = cb_err_def[kind];
cb->cb_err_arg = arg;
}
return 0;
}
/** @} */
/**
* @name Overwriting
* @{
*/
/**
* Overwrite internal calls to nl_recvmsgs()
* @arg cb callback set
* @arg func replacement callback for nl_recvmsgs()
*/
void nl_cb_overwrite_recvmsgs(struct nl_cb *cb,
int (*func)(struct nl_sock *, struct nl_cb *))
{
cb->cb_recvmsgs_ow = func;
}
/**
* Overwrite internal calls to nl_recv()
* @arg cb callback set
* @arg func replacement callback for nl_recv()
*/
void nl_cb_overwrite_recv(struct nl_cb *cb,
int (*func)(struct nl_sock *, struct sockaddr_nl *,
unsigned char **, struct ucred **))
{
cb->cb_recv_ow = func;
}
/**
* Overwrite internal calls to nl_send()
* @arg cb callback set
* @arg func replacement callback for nl_send()
*/
void nl_cb_overwrite_send(struct nl_cb *cb,
int (*func)(struct nl_sock *, struct nl_msg *))
{
cb->cb_send_ow = func;
}
/** @} */
/** @} */