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diff --git a/src/core/msgb.c b/src/core/msgb.c
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+/* (C) 2008 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * 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.
+ *
+ */
+
+/*! \addtogroup msgb
+ * @{
+ *
+ * libosmocore message buffers, inspired by Linux kernel skbuff
+ *
+ * Inspired by the 'struct skbuff' of the Linux kernel, we implement a
+ * 'struct msgb' which we use for handling network
+ * packets aka messages aka PDUs.
+ *
+ * A msgb consists of
+ * * a header with some metadata, such as
+ * * a linked list header for message queues or the like
+ * * pointers to the headers of various protocol layers inside
+ * the packet
+ * * a data section consisting of
+ * * headroom, i.e. space in front of the message, to allow
+ * for additional headers being pushed in front of the current
+ * data
+ * * the currently occupied data for the message
+ * * tailroom, i.e. space at the end of the message, to
+ * allow more data to be added after the end of the current
+ * data
+ *
+ * We have plenty of utility functions around the \ref msgb:
+ * * allocation / release
+ * * enqueue / dequeue from/to message queues
+ * * prepending (pushing) and appending (putting) data
+ * * copying / resizing
+ * * hex-dumping to a string for debug purposes
+ *
+ * \file msgb.c
+ */
+
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <stdarg.h>
+#include <errno.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/logging.h>
+
+/*! Allocate a new message buffer from given talloc context
+ * \param[in] ctx talloc context from which to allocate
+ * \param[in] size Length in octets, including headroom
+ * \param[in] name Human-readable name to be associated with msgb
+ * \returns dynamically-allocated \ref msgb
+ *
+ * This function allocates a 'struct msgb' as well as the underlying
+ * memory buffer for the actual message data (size specified by \a size)
+ * using the talloc memory context previously set by \ref msgb_set_talloc_ctx
+ */
+struct msgb *msgb_alloc_c(const void *ctx, uint16_t size, const char *name)
+{
+ struct msgb *msg;
+
+ msg = talloc_named_const(ctx, sizeof(*msg) + size, name);
+ if (!msg) {
+ LOGP(DLGLOBAL, LOGL_FATAL, "Unable to allocate a msgb: "
+ "name='%s', size=%u\n", name, size);
+ return NULL;
+ }
+
+ /* Manually zero-initialize allocated memory */
+ memset(msg, 0x00, sizeof(*msg) + size);
+
+ msg->data_len = size;
+ msg->len = 0;
+ msg->data = msg->_data;
+ msg->head = msg->_data;
+ msg->tail = msg->_data;
+
+ return msg;
+}
+
+/* default msgb allocation context for msgb_alloc() */
+void *tall_msgb_ctx = NULL;
+
+/*! Allocate a new message buffer from tall_msgb_ctx
+ * \param[in] size Length in octets, including headroom
+ * \param[in] name Human-readable name to be associated with msgb
+ * \returns dynamically-allocated \ref msgb
+ *
+ * This function allocates a 'struct msgb' as well as the underlying
+ * memory buffer for the actual message data (size specified by \a size)
+ * using the talloc memory context previously set by \ref msgb_set_talloc_ctx
+ */
+struct msgb *msgb_alloc(uint16_t size, const char *name)
+{
+ return msgb_alloc_c(tall_msgb_ctx, size, name);
+}
+
+
+/*! Release given message buffer
+ * \param[in] m Message buffer to be freed
+ */
+void msgb_free(struct msgb *m)
+{
+ talloc_free(m);
+}
+
+/*! Enqueue message buffer to tail of a queue
+ * \param[in] queue linked list header of queue
+ * \param[in] msg message buffer to be added to the queue
+ *
+ * The function will append the specified message buffer \a msg to the
+ * queue implemented by \ref llist_head \a queue
+ */
+void msgb_enqueue(struct llist_head *queue, struct msgb *msg)
+{
+ llist_add_tail(&msg->list, queue);
+}
+
+/*! Dequeue message buffer from head of queue
+ * \param[in] queue linked list header of queue
+ * \returns message buffer (if any) or NULL if queue empty
+ *
+ * The function will remove the first message buffer from the queue
+ * implemented by \ref llist_head \a queue.
+ */
+struct msgb *msgb_dequeue(struct llist_head *queue)
+{
+ struct llist_head *lh;
+
+ if (llist_empty(queue))
+ return NULL;
+
+ lh = queue->next;
+
+ if (lh) {
+ llist_del(lh);
+ return llist_entry(lh, struct msgb, list);
+ } else
+ return NULL;
+}
+
+/*! Re-set all message buffer pointers
+ * \param[in] msg message buffer that is to be resetted
+ *
+ * This will re-set the various internal pointers into the underlying
+ * message buffer, i.e. remove all headroom and treat the msgb as
+ * completely empty. It also initializes the control buffer to zero.
+ */
+void msgb_reset(struct msgb *msg)
+{
+ msg->len = 0;
+ msg->data = msg->_data;
+ msg->head = msg->_data;
+ msg->tail = msg->_data;
+
+ msg->trx = NULL;
+ msg->lchan = NULL;
+ msg->l2h = NULL;
+ msg->l3h = NULL;
+ msg->l4h = NULL;
+
+ memset(&msg->cb, 0, sizeof(msg->cb));
+}
+
+/*! get pointer to data section of message buffer
+ * \param[in] msg message buffer
+ * \returns pointer to data section of message buffer
+ */
+uint8_t *msgb_data(const struct msgb *msg)
+{
+ return msg->data;
+}
+
+/*! Compare and print: check data in msgb against given data and print errors if any
+ * \param[in] file text prefix, usually __FILE__, ignored if print == false
+ * \param[in] line numeric prefix, usually __LINE__, ignored if print == false
+ * \param[in] func text prefix, usually __func__, ignored if print == false
+ * \param[in] level while layer (L1, L2 etc) data should be compared against
+ * \param[in] msg message buffer
+ * \param[in] data expected data
+ * \param[in] len length of data
+ * \param[in] print boolean indicating whether we should print anything to stdout
+ * \returns boolean indicating whether msgb content is equal to a given data
+ *
+ * This function is not intended to be called directly but rather used through corresponding macro wrappers.
+ */
+bool _msgb_eq(const char *file, size_t line, const char *func, uint8_t level,
+ const struct msgb *msg, const uint8_t *data, size_t len, bool print)
+{
+ const char *m_dump;
+ unsigned int m_len, i;
+ uint8_t *m_data;
+
+ if (!msg) {
+ if (print)
+ LOGPSRC(DLGLOBAL, LOGL_FATAL, file, line, "%s() NULL msg comparison\n", func);
+ return false;
+ }
+
+ if (!data) {
+ if (print)
+ LOGPSRC(DLGLOBAL, LOGL_FATAL, file, line, "%s() NULL comparison data\n", func);
+ return false;
+ }
+
+ switch (level) {
+ case 0:
+ m_len = msgb_length(msg);
+ m_data = msgb_data(msg);
+ m_dump = print ? msgb_hexdump(msg) : NULL;
+ break;
+ case 1:
+ m_len = msgb_l1len(msg);
+ m_data = msgb_l1(msg);
+ m_dump = print ? msgb_hexdump_l1(msg) : NULL;
+ break;
+ case 2:
+ m_len = msgb_l2len(msg);
+ m_data = msgb_l2(msg);
+ m_dump = print ? msgb_hexdump_l2(msg) : NULL;
+ break;
+ case 3:
+ m_len = msgb_l3len(msg);
+ m_data = msgb_l3(msg);
+ m_dump = print ? msgb_hexdump_l3(msg) : NULL;
+ break;
+ case 4:
+ m_len = msgb_l4len(msg);
+ m_data = msgb_l4(msg);
+ m_dump = print ? msgb_hexdump_l4(msg) : NULL;
+ break;
+ default:
+ LOGPSRC(DLGLOBAL, LOGL_FATAL, file, line,
+ "%s() FIXME: unexpected comparison level %u\n", func, level);
+ return false;
+ }
+
+ if (m_len != len) {
+ if (print)
+ LOGPSRC(DLGLOBAL, LOGL_FATAL, file, line,
+ "%s() Length mismatch: %d != %zu, %s\n", func, m_len, len, m_dump);
+ return false;
+ }
+
+ if (memcmp(m_data, data, len) == 0)
+ return true;
+
+ if (!print)
+ return false;
+
+ LOGPSRC(DLGLOBAL, LOGL_FATAL, file, line,
+ "%s() L%u data mismatch:\nexpected %s\n ", func, level, osmo_hexdump(data, len));
+
+ for(i = 0; i < len; i++)
+ if (data[i] != m_data[i]) {
+ LOGPC(DLGLOBAL, LOGL_FATAL, "!!\n");
+ break;
+ } else
+ LOGPC(DLGLOBAL, LOGL_FATAL, ".. ");
+
+ LOGPC(DLGLOBAL, LOGL_FATAL, " msgb %s\n", osmo_hexdump(m_data, len));
+
+ return false;
+}
+
+/*! get length of message buffer
+ * \param[in] msg message buffer
+ * \returns length of data section in message buffer
+ */
+uint16_t msgb_length(const struct msgb *msg)
+{
+ return msg->len;
+}
+
+/*! Set the talloc context for \ref msgb_alloc
+ * Deprecated, use msgb_talloc_ctx_init() instead.
+ * \param[in] ctx talloc context to be used as root for msgb allocations
+ */
+void msgb_set_talloc_ctx(void *ctx)
+{
+ tall_msgb_ctx = ctx;
+}
+
+/*! Initialize a msgb talloc context for \ref msgb_alloc.
+ * Create a talloc context called "msgb". If \a pool_size is 0, create a named
+ * const as msgb talloc context. If \a pool_size is nonzero, create a talloc
+ * pool, possibly for faster msgb allocations (see talloc_pool()).
+ * \param[in] root_ctx talloc context used as parent for the new "msgb" ctx.
+ * \param[in] pool_size if nonzero, create a talloc pool of this size.
+ * \returns the new msgb talloc context, e.g. for reporting
+ */
+void *msgb_talloc_ctx_init(void *root_ctx, unsigned int pool_size)
+{
+ if (!pool_size)
+ tall_msgb_ctx = talloc_size(root_ctx, 0);
+ else
+ tall_msgb_ctx = talloc_pool(root_ctx, pool_size);
+ talloc_set_name_const(tall_msgb_ctx, "msgb");
+ return tall_msgb_ctx;
+}
+
+/*! Copy an msgb with memory reallocation.
+ *
+ * This function allocates a new msgb with new_len size, copies the data buffer of msg,
+ * and adjusts the pointers (incl l1h-l4h) accordingly. The cb part is not copied.
+ * \param[in] ctx talloc context on which allocation happens
+ * \param[in] msg The old msgb object
+ * \param[in] new_len The length of new msgb object
+ * \param[in] name Human-readable name to be associated with new msgb
+ */
+struct msgb *msgb_copy_resize_c(const void *ctx, const struct msgb *msg, uint16_t new_len, const char *name)
+{
+ struct msgb *new_msg;
+
+ if (new_len < msgb_length(msg)) {
+ LOGP(DLGLOBAL, LOGL_ERROR,
+ "Data from old msgb (%u bytes) won't fit into new msgb (%u bytes) after reallocation\n",
+ msgb_length(msg), new_len);
+ return NULL;
+ }
+
+ new_msg = msgb_alloc_c(ctx, new_len, name);
+ if (!new_msg)
+ return NULL;
+
+ /* copy header */
+ new_msg->len = msg->len;
+ new_msg->data += msg->data - msg->_data;
+ new_msg->head += msg->head - msg->_data;
+ new_msg->tail += msg->tail - msg->_data;
+
+ /* copy data */
+ memcpy(new_msg->data, msg->data, msgb_length(msg));
+
+ if (msg->l1h)
+ new_msg->l1h = new_msg->_data + (msg->l1h - msg->_data);
+ if (msg->l2h)
+ new_msg->l2h = new_msg->_data + (msg->l2h - msg->_data);
+ if (msg->l3h)
+ new_msg->l3h = new_msg->_data + (msg->l3h - msg->_data);
+ if (msg->l4h)
+ new_msg->l4h = new_msg->_data + (msg->l4h - msg->_data);
+
+ return new_msg;
+}
+
+/*! Copy an msgb with memory reallocation.
+ *
+ * This function allocates a new msgb with new_len size, copies the data buffer of msg,
+ * and adjusts the pointers (incl l1h-l4h) accordingly. The cb part is not copied.
+ * \param[in] msg The old msgb object
+ * \param[in] name Human-readable name to be associated with new msgb
+ */
+struct msgb *msgb_copy_resize(const struct msgb *msg, uint16_t new_len, const char *name)
+{
+ return msgb_copy_resize_c(tall_msgb_ctx, msg, new_len, name);
+}
+
+/*! Copy an msgb.
+ *
+ * This function allocates a new msgb, copies the data buffer of msg,
+ * and adjusts the pointers (incl l1h-l4h) accordingly. The cb part
+ * is not copied.
+ * \param[in] ctx talloc context on which allocation happens
+ * \param[in] msg The old msgb object
+ * \param[in] name Human-readable name to be associated with msgb
+ */
+struct msgb *msgb_copy_c(const void *ctx, const struct msgb *msg, const char *name)
+{
+ return msgb_copy_resize_c(ctx, msg, msg->data_len, name);
+}
+
+/*! Copy an msgb.
+ *
+ * This function allocates a new msgb, copies the data buffer of msg,
+ * and adjusts the pointers (incl l1h-l4h) accordingly. The cb part
+ * is not copied.
+ * \param[in] msg The old msgb object
+ * \param[in] name Human-readable name to be associated with msgb
+ */
+struct msgb *msgb_copy(const struct msgb *msg, const char *name)
+{
+ return msgb_copy_c(tall_msgb_ctx, msg, name);
+}
+
+/*! Resize an area within an msgb
+ *
+ * This resizes a sub area of the msgb data and adjusts the pointers (incl
+ * l1h-l4h) accordingly. The cb part is not updated. If the area is extended,
+ * the contents of the extension is undefined. The complete sub area must be a
+ * part of [data,tail].
+ *
+ * \param[inout] msg The msgb object
+ * \param[in] area A pointer to the sub-area
+ * \param[in] old_size The old size of the sub-area
+ * \param[in] new_size The new size of the sub-area
+ * \returns 0 on success, -1 if there is not enough space to extend the area
+ */
+int msgb_resize_area(struct msgb *msg, uint8_t *area,
+ int old_size, int new_size)
+{
+ int rc;
+ uint8_t *post_start = area + old_size;
+ int pre_len = area - msg->data;
+ int post_len = msg->len - old_size - pre_len;
+ int delta_size = new_size - old_size;
+
+ if (old_size < 0 || new_size < 0)
+ MSGB_ABORT(msg, "Negative sizes are not allowed\n");
+ if (area < msg->data || post_start > msg->tail)
+ MSGB_ABORT(msg, "Sub area is not fully contained in the msg data\n");
+
+ if (delta_size == 0)
+ return 0;
+
+ if (delta_size > 0) {
+ rc = msgb_trim(msg, msg->len + delta_size);
+ if (rc < 0)
+ return rc;
+ }
+
+ memmove(area + new_size, area + old_size, post_len);
+
+ if (msg->l1h >= post_start)
+ msg->l1h += delta_size;
+ if (msg->l2h >= post_start)
+ msg->l2h += delta_size;
+ if (msg->l3h >= post_start)
+ msg->l3h += delta_size;
+ if (msg->l4h >= post_start)
+ msg->l4h += delta_size;
+
+ if (delta_size < 0)
+ msgb_trim(msg, msg->len + delta_size);
+
+ return 0;
+}
+
+
+/*! fill user-provided buffer with hexdump of the msg.
+ * \param[out] buf caller-allocated buffer for output string
+ * \param[in] buf_len length of buf
+ * \param[in] msg message buffer to be dumped
+ * \returns buf
+ */
+char *msgb_hexdump_buf(char *buf, size_t buf_len, const struct msgb *msg)
+{
+ unsigned int buf_offs = 0;
+ int nchars;
+ const unsigned char *start = msg->data;
+ const unsigned char *lxhs[4];
+ unsigned int i;
+
+ lxhs[0] = msg->l1h;
+ lxhs[1] = msg->l2h;
+ lxhs[2] = msg->l3h;
+ lxhs[3] = msg->l4h;
+
+ for (i = 0; i < ARRAY_SIZE(lxhs); i++) {
+ if (!lxhs[i])
+ continue;
+
+ if (lxhs[i] < msg->head)
+ continue;
+ if (lxhs[i] > msg->head + msg->data_len)
+ continue;
+ if (lxhs[i] > msg->tail)
+ continue;
+ if (lxhs[i] < msg->data || lxhs[i] > msg->tail) {
+ nchars = snprintf(buf + buf_offs, buf_len - buf_offs,
+ "(L%d=data%+" PRIdPTR ") ",
+ i+1, lxhs[i] - msg->data);
+ buf_offs += nchars;
+ continue;
+ }
+ if (lxhs[i] < start) {
+ nchars = snprintf(buf + buf_offs, buf_len - buf_offs,
+ "(L%d%+" PRIdPTR ") ", i+1,
+ start - lxhs[i]);
+ buf_offs += nchars;
+ continue;
+ }
+ nchars = snprintf(buf + buf_offs, buf_len - buf_offs,
+ "%s[L%d]> ",
+ osmo_hexdump(start, lxhs[i] - start),
+ i+1);
+ if (nchars < 0 || nchars + buf_offs >= buf_len)
+ return "ERROR";
+
+ buf_offs += nchars;
+ start = lxhs[i];
+ }
+ nchars = snprintf(buf + buf_offs, buf_len - buf_offs,
+ "%s", osmo_hexdump(start, msg->tail - start));
+ if (nchars < 0 || nchars + buf_offs >= buf_len)
+ return "ERROR";
+
+ buf_offs += nchars;
+
+ for (i = 0; i < ARRAY_SIZE(lxhs); i++) {
+ if (!lxhs[i])
+ continue;
+
+ if (lxhs[i] < msg->head || lxhs[i] > msg->head + msg->data_len) {
+ nchars = snprintf(buf + buf_offs, buf_len - buf_offs,
+ "(L%d out of range) ", i+1);
+ } else if (lxhs[i] <= msg->data + msg->data_len &&
+ lxhs[i] > msg->tail) {
+ nchars = snprintf(buf + buf_offs, buf_len - buf_offs,
+ "(L%d=tail%+" PRIdPTR ") ",
+ i+1, lxhs[i] - msg->tail);
+ } else
+ continue;
+
+ if (nchars < 0 || nchars + buf_offs >= buf_len)
+ return "ERROR";
+ buf_offs += nchars;
+ }
+
+ return buf;
+}
+
+/*! Return a (static) buffer containing a hexdump of the msg.
+ * \param[in] msg message buffer
+ * \returns a pointer to a static char array
+ */
+const char *msgb_hexdump(const struct msgb *msg)
+{
+ static __thread char buf[4100];
+ return msgb_hexdump_buf(buf, sizeof(buf), msg);
+}
+
+/*! Return a dynamically allocated buffer containing a hexdump of the msg
+ * \param[in] ctx talloc context from where to allocate the output string
+ * \param[in] msg message buffer
+ * \returns a pointer to a static char array
+ */
+char *msgb_hexdump_c(const void *ctx, const struct msgb *msg)
+{
+ size_t buf_len = msgb_length(msg) * 3 + 100;
+ char *buf = talloc_size(ctx, buf_len);
+ if (!buf)
+ return NULL;
+ return msgb_hexdump_buf(buf, buf_len, msg);
+}
+
+/*! Print a string to the end of message buffer.
+ * \param[in] msgb message buffer.
+ * \param[in] format format string.
+ * \returns 0 on success, -EINVAL on error.
+ *
+ * The resulting string is printed to the msgb without a trailing nul
+ * character. A nul following the data tail may be written as an implementation
+ * detail, but a trailing nul is never part of the msgb data in terms of
+ * msgb_length().
+ *
+ * Note: the tailroom must always be one byte longer than the string to be
+ * written. The msgb is filled only up to tailroom=1. This is an implementation
+ * detail that allows leaving a nul character behind the valid data.
+ *
+ * In case of error, the msgb remains unchanged, though data may have been
+ * written to the (unused) memory after the tail pointer.
+ */
+int msgb_printf(struct msgb *msgb, const char *format, ...)
+{
+ va_list args;
+ int str_len;
+ int rc = 0;
+
+ OSMO_ASSERT(msgb);
+ OSMO_ASSERT(format);
+
+ /* Regardless of what we plan to add to the buffer, we must at least
+ * be able to store a string terminator (nullstring) */
+ if (msgb_tailroom(msgb) < 1)
+ return -EINVAL;
+
+ va_start(args, format);
+
+ str_len =
+ vsnprintf((char *)msgb->tail, msgb_tailroom(msgb), format, args);
+
+ if (str_len >= msgb_tailroom(msgb) || str_len < 0) {
+ rc = -EINVAL;
+ } else
+ msgb_put(msgb, str_len);
+
+ va_end(args);
+ return rc;
+}
+
+/*! @} */
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