Diff: lwip/api/netbuf.c

Revision:

0:b2805b6888dc

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lwip/api/netbuf.c	Mon Jun 20 01:40:20 2016 +0000
@@ -0,0 +1,245 @@
+/**
+ * @file
+ * Network buffer management
+ *
+ */
+ 
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/netbuf.h"
+#include "lwip/memp.h"
+
+#include <string.h>
+
+/**
+ * Create (allocate) and initialize a new netbuf.
+ * The netbuf doesn't yet contain a packet buffer!
+ *
+ * @return a pointer to a new netbuf
+ *         NULL on lack of memory
+ */
+struct
+netbuf *netbuf_new(void)
+{
+  struct netbuf *buf;
+
+  buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);
+  if (buf != NULL) {
+    buf->p = NULL;
+    buf->ptr = NULL;
+    ip_addr_set_any(&buf->addr);
+    buf->port = 0;
+#if LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY
+#if LWIP_CHECKSUM_ON_COPY
+    buf->flags = 0;
+#endif /* LWIP_CHECKSUM_ON_COPY */
+    buf->toport_chksum = 0;
+#if LWIP_NETBUF_RECVINFO
+    ip_addr_set_any(&buf->toaddr);
+#endif /* LWIP_NETBUF_RECVINFO */
+#endif /* LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY */
+    return buf;
+  } else {
+    return NULL;
+  }
+}
+
+/**
+ * Deallocate a netbuf allocated by netbuf_new().
+ *
+ * @param buf pointer to a netbuf allocated by netbuf_new()
+ */
+void
+netbuf_delete(struct netbuf *buf)
+{
+  if (buf != NULL) {
+    if (buf->p != NULL) {
+      pbuf_free(buf->p);
+      buf->p = buf->ptr = NULL;
+    }
+    memp_free(MEMP_NETBUF, buf);
+  }
+}
+
+/**
+ * Allocate memory for a packet buffer for a given netbuf.
+ *
+ * @param buf the netbuf for which to allocate a packet buffer
+ * @param size the size of the packet buffer to allocate
+ * @return pointer to the allocated memory
+ *         NULL if no memory could be allocated
+ */
+void *
+netbuf_alloc(struct netbuf *buf, u16_t size)
+{
+  LWIP_ERROR("netbuf_alloc: invalid buf", (buf != NULL), return NULL;);
+
+  /* Deallocate any previously allocated memory. */
+  if (buf->p != NULL) {
+    pbuf_free(buf->p);
+  }
+  buf->p = pbuf_alloc(PBUF_TRANSPORT, size, PBUF_RAM);
+  if (buf->p == NULL) {
+     return NULL;
+  }
+  LWIP_ASSERT("check that first pbuf can hold size",
+             (buf->p->len >= size));
+  buf->ptr = buf->p;
+  return buf->p->payload;
+}
+
+/**
+ * Free the packet buffer included in a netbuf
+ *
+ * @param buf pointer to the netbuf which contains the packet buffer to free
+ */
+void
+netbuf_free(struct netbuf *buf)
+{
+  LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
+  if (buf->p != NULL) {
+    pbuf_free(buf->p);
+  }
+  buf->p = buf->ptr = NULL;
+}
+
+/**
+ * Let a netbuf reference existing (non-volatile) data.
+ *
+ * @param buf netbuf which should reference the data
+ * @param dataptr pointer to the data to reference
+ * @param size size of the data
+ * @return ERR_OK if data is referenced
+ *         ERR_MEM if data couldn't be referenced due to lack of memory
+ */
+err_t
+netbuf_ref(struct netbuf *buf, const void *dataptr, u16_t size)
+{
+  LWIP_ERROR("netbuf_ref: invalid buf", (buf != NULL), return ERR_ARG;);
+  if (buf->p != NULL) {
+    pbuf_free(buf->p);
+  }
+  buf->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_REF);
+  if (buf->p == NULL) {
+    buf->ptr = NULL;
+    return ERR_MEM;
+  }
+  buf->p->payload = (void*)dataptr;
+  buf->p->len = buf->p->tot_len = size;
+  buf->ptr = buf->p;
+  return ERR_OK;
+}
+
+/**
+ * Chain one netbuf to another (@see pbuf_chain)
+ *
+ * @param head the first netbuf
+ * @param tail netbuf to chain after head, freed by this function, may not be reference after returning
+ */
+void
+netbuf_chain(struct netbuf *head, struct netbuf *tail)
+{
+  LWIP_ERROR("netbuf_ref: invalid head", (head != NULL), return;);
+  LWIP_ERROR("netbuf_chain: invalid tail", (tail != NULL), return;);
+  pbuf_cat(head->p, tail->p);
+  head->ptr = head->p;
+  memp_free(MEMP_NETBUF, tail);
+}
+
+/**
+ * Get the data pointer and length of the data inside a netbuf.
+ *
+ * @param buf netbuf to get the data from
+ * @param dataptr pointer to a void pointer where to store the data pointer
+ * @param len pointer to an u16_t where the length of the data is stored
+ * @return ERR_OK if the information was retreived,
+ *         ERR_BUF on error.
+ */
+err_t
+netbuf_data(struct netbuf *buf, void **dataptr, u16_t *len)
+{
+  LWIP_ERROR("netbuf_data: invalid buf", (buf != NULL), return ERR_ARG;);
+  LWIP_ERROR("netbuf_data: invalid dataptr", (dataptr != NULL), return ERR_ARG;);
+  LWIP_ERROR("netbuf_data: invalid len", (len != NULL), return ERR_ARG;);
+
+  if (buf->ptr == NULL) {
+    return ERR_BUF;
+  }
+  *dataptr = buf->ptr->payload;
+  *len = buf->ptr->len;
+  return ERR_OK;
+}
+
+/**
+ * Move the current data pointer of a packet buffer contained in a netbuf
+ * to the next part.
+ * The packet buffer itself is not modified.
+ *
+ * @param buf the netbuf to modify
+ * @return -1 if there is no next part
+ *         1  if moved to the next part but now there is no next part
+ *         0  if moved to the next part and there are still more parts
+ */
+s8_t
+netbuf_next(struct netbuf *buf)
+{
+  LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return -1;);
+  if (buf->ptr->next == NULL) {
+    return -1;
+  }
+  buf->ptr = buf->ptr->next;
+  if (buf->ptr->next == NULL) {
+    return 1;
+  }
+  return 0;
+}
+
+/**
+ * Move the current data pointer of a packet buffer contained in a netbuf
+ * to the beginning of the packet.
+ * The packet buffer itself is not modified.
+ *
+ * @param buf the netbuf to modify
+ */
+void
+netbuf_first(struct netbuf *buf)
+{
+  LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
+  buf->ptr = buf->p;
+}
+
+#endif /* LWIP_NETCONN */