diff options
Diffstat (limited to 'src/core/msgb.c')
-rw-r--r-- | src/core/msgb.c | 607 |
1 files changed, 607 insertions, 0 deletions
diff --git a/src/core/msgb.c b/src/core/msgb.c new file mode 100644 index 00000000..713510c6 --- /dev/null +++ b/src/core/msgb.c @@ -0,0 +1,607 @@ +/* (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; +} + +/*! @} */ |