![Jouni Malinen](/assets/img/avatar_default.png)
Use an explicit pointer to the beginning of the buffer and a flag to indicate whether that is to external data or not. This avoids a branch whenever accessing the buffer and helps some static analyzers to understand the wpabuf memory uses better. Signed-hostap: Jouni Malinen <j@w1.fi>
303 lines
6.7 KiB
C
303 lines
6.7 KiB
C
/*
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* Dynamic data buffer
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* Copyright (c) 2007-2012, Jouni Malinen <j@w1.fi>
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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*/
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#include "includes.h"
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#include "common.h"
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#include "trace.h"
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#include "wpabuf.h"
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#ifdef WPA_TRACE
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#define WPABUF_MAGIC 0x51a974e3
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struct wpabuf_trace {
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unsigned int magic;
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};
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static struct wpabuf_trace * wpabuf_get_trace(const struct wpabuf *buf)
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{
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return (struct wpabuf_trace *)
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((const u8 *) buf - sizeof(struct wpabuf_trace));
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}
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#endif /* WPA_TRACE */
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static void wpabuf_overflow(const struct wpabuf *buf, size_t len)
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{
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#ifdef WPA_TRACE
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struct wpabuf_trace *trace = wpabuf_get_trace(buf);
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if (trace->magic != WPABUF_MAGIC) {
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wpa_printf(MSG_ERROR, "wpabuf: invalid magic %x",
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trace->magic);
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}
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#endif /* WPA_TRACE */
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wpa_printf(MSG_ERROR, "wpabuf %p (size=%lu used=%lu) overflow len=%lu",
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buf, (unsigned long) buf->size, (unsigned long) buf->used,
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(unsigned long) len);
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wpa_trace_show("wpabuf overflow");
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abort();
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}
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int wpabuf_resize(struct wpabuf **_buf, size_t add_len)
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{
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struct wpabuf *buf = *_buf;
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#ifdef WPA_TRACE
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struct wpabuf_trace *trace;
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#endif /* WPA_TRACE */
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if (buf == NULL) {
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*_buf = wpabuf_alloc(add_len);
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return *_buf == NULL ? -1 : 0;
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}
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#ifdef WPA_TRACE
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trace = wpabuf_get_trace(buf);
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if (trace->magic != WPABUF_MAGIC) {
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wpa_printf(MSG_ERROR, "wpabuf: invalid magic %x",
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trace->magic);
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wpa_trace_show("wpabuf_resize invalid magic");
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abort();
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}
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#endif /* WPA_TRACE */
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if (buf->used + add_len > buf->size) {
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unsigned char *nbuf;
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if (buf->flags & WPABUF_FLAG_EXT_DATA) {
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nbuf = os_realloc(buf->buf, buf->used + add_len);
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if (nbuf == NULL)
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return -1;
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os_memset(nbuf + buf->used, 0, add_len);
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buf->buf = nbuf;
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} else {
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#ifdef WPA_TRACE
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nbuf = os_realloc(trace, sizeof(struct wpabuf_trace) +
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sizeof(struct wpabuf) +
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buf->used + add_len);
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if (nbuf == NULL)
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return -1;
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trace = (struct wpabuf_trace *) nbuf;
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buf = (struct wpabuf *) (trace + 1);
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os_memset(nbuf + sizeof(struct wpabuf_trace) +
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sizeof(struct wpabuf) + buf->used, 0,
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add_len);
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#else /* WPA_TRACE */
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nbuf = os_realloc(buf, sizeof(struct wpabuf) +
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buf->used + add_len);
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if (nbuf == NULL)
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return -1;
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buf = (struct wpabuf *) nbuf;
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os_memset(nbuf + sizeof(struct wpabuf) + buf->used, 0,
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add_len);
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#endif /* WPA_TRACE */
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buf->buf = (u8 *) (buf + 1);
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*_buf = buf;
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}
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buf->size = buf->used + add_len;
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}
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return 0;
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}
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/**
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* wpabuf_alloc - Allocate a wpabuf of the given size
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* @len: Length for the allocated buffer
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* Returns: Buffer to the allocated wpabuf or %NULL on failure
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*/
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struct wpabuf * wpabuf_alloc(size_t len)
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{
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#ifdef WPA_TRACE
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struct wpabuf_trace *trace = os_zalloc(sizeof(struct wpabuf_trace) +
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sizeof(struct wpabuf) + len);
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struct wpabuf *buf;
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if (trace == NULL)
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return NULL;
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trace->magic = WPABUF_MAGIC;
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buf = (struct wpabuf *) (trace + 1);
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#else /* WPA_TRACE */
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struct wpabuf *buf = os_zalloc(sizeof(struct wpabuf) + len);
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if (buf == NULL)
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return NULL;
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#endif /* WPA_TRACE */
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buf->size = len;
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buf->buf = (u8 *) (buf + 1);
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return buf;
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}
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struct wpabuf * wpabuf_alloc_ext_data(u8 *data, size_t len)
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{
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#ifdef WPA_TRACE
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struct wpabuf_trace *trace = os_zalloc(sizeof(struct wpabuf_trace) +
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sizeof(struct wpabuf));
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struct wpabuf *buf;
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if (trace == NULL)
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return NULL;
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trace->magic = WPABUF_MAGIC;
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buf = (struct wpabuf *) (trace + 1);
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#else /* WPA_TRACE */
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struct wpabuf *buf = os_zalloc(sizeof(struct wpabuf));
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if (buf == NULL)
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return NULL;
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#endif /* WPA_TRACE */
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buf->size = len;
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buf->used = len;
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buf->buf = data;
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buf->flags |= WPABUF_FLAG_EXT_DATA;
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return buf;
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}
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struct wpabuf * wpabuf_alloc_copy(const void *data, size_t len)
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{
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struct wpabuf *buf = wpabuf_alloc(len);
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if (buf)
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wpabuf_put_data(buf, data, len);
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return buf;
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}
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struct wpabuf * wpabuf_dup(const struct wpabuf *src)
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{
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struct wpabuf *buf = wpabuf_alloc(wpabuf_len(src));
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if (buf)
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wpabuf_put_data(buf, wpabuf_head(src), wpabuf_len(src));
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return buf;
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}
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/**
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* wpabuf_free - Free a wpabuf
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* @buf: wpabuf buffer
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*/
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void wpabuf_free(struct wpabuf *buf)
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{
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#ifdef WPA_TRACE
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struct wpabuf_trace *trace;
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if (buf == NULL)
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return;
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trace = wpabuf_get_trace(buf);
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if (trace->magic != WPABUF_MAGIC) {
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wpa_printf(MSG_ERROR, "wpabuf_free: invalid magic %x",
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trace->magic);
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wpa_trace_show("wpabuf_free magic mismatch");
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abort();
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}
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if (buf->flags & WPABUF_FLAG_EXT_DATA)
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os_free(buf->buf);
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os_free(trace);
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#else /* WPA_TRACE */
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if (buf == NULL)
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return;
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if (buf->flags & WPABUF_FLAG_EXT_DATA)
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os_free(buf->buf);
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os_free(buf);
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#endif /* WPA_TRACE */
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}
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void * wpabuf_put(struct wpabuf *buf, size_t len)
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{
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void *tmp = wpabuf_mhead_u8(buf) + wpabuf_len(buf);
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buf->used += len;
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if (buf->used > buf->size) {
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wpabuf_overflow(buf, len);
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}
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return tmp;
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}
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/**
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* wpabuf_concat - Concatenate two buffers into a newly allocated one
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* @a: First buffer
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* @b: Second buffer
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* Returns: wpabuf with concatenated a + b data or %NULL on failure
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*
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* Both buffers a and b will be freed regardless of the return value. Input
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* buffers can be %NULL which is interpreted as an empty buffer.
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*/
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struct wpabuf * wpabuf_concat(struct wpabuf *a, struct wpabuf *b)
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{
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struct wpabuf *n = NULL;
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size_t len = 0;
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if (b == NULL)
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return a;
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if (a)
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len += wpabuf_len(a);
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if (b)
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len += wpabuf_len(b);
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n = wpabuf_alloc(len);
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if (n) {
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if (a)
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wpabuf_put_buf(n, a);
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if (b)
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wpabuf_put_buf(n, b);
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}
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wpabuf_free(a);
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wpabuf_free(b);
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return n;
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}
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/**
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* wpabuf_zeropad - Pad buffer with 0x00 octets (prefix) to specified length
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* @buf: Buffer to be padded
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* @len: Length for the padded buffer
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* Returns: wpabuf padded to len octets or %NULL on failure
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*
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* If buf is longer than len octets or of same size, it will be returned as-is.
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* Otherwise a new buffer is allocated and prefixed with 0x00 octets followed
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* by the source data. The source buffer will be freed on error, i.e., caller
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* will only be responsible on freeing the returned buffer. If buf is %NULL,
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* %NULL will be returned.
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*/
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struct wpabuf * wpabuf_zeropad(struct wpabuf *buf, size_t len)
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{
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struct wpabuf *ret;
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size_t blen;
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if (buf == NULL)
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return NULL;
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blen = wpabuf_len(buf);
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if (blen >= len)
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return buf;
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ret = wpabuf_alloc(len);
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if (ret) {
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os_memset(wpabuf_put(ret, len - blen), 0, len - blen);
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wpabuf_put_buf(ret, buf);
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}
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wpabuf_free(buf);
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return ret;
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}
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void wpabuf_printf(struct wpabuf *buf, char *fmt, ...)
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{
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va_list ap;
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void *tmp = wpabuf_mhead_u8(buf) + wpabuf_len(buf);
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int res;
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va_start(ap, fmt);
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res = vsnprintf(tmp, buf->size - buf->used, fmt, ap);
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va_end(ap);
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if (res < 0 || (size_t) res >= buf->size - buf->used)
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wpabuf_overflow(buf, res);
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buf->used += res;
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}
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