Fixed bug #20429: use the new pbuf_copy_partial instead of the old copy_from_pbuf, which illegally modified the given pbuf; Introduced pbuf_copy_partial, making netbuf_copy_partial use this function.

CHANGELOG

@@ -19,6 +19,10 @@ HISTORY
 
   ++ New features:
 
+  2007-07-25 Simon Goldschmidt
+  * api_lib.c, ip_frag.c, pbuf.c, api.h, pbuf.h: Introduced pbuf_copy_partial,
+    making netbuf_copy_partial use this function.
+
   2007-07-25 Simon Goldschmidt
   * tcp_in.c: Fix bug #20506: Slow start / initial congestion window starts with
     2 * mss (instead of 1 * mss previously) to comply with some newer RFCs and
@@ -252,6 +256,10 @@ HISTORY
 
   ++ Bug fixes:
 
+  2007-07-25 Simon Goldschmidt
+  * ip_frag.c: Fixed bug #20429: use the new pbuf_copy_partial instead of the old
+    copy_from_pbuf, which illegally modified the given pbuf.
+
   2007-07-25 Simon Goldschmidt
   * tcp_out.c: tcp_enqueue: pcb->snd_queuelen didn't work for chaine PBUF_RAMs:
     changed snd_queuelen++ to snd_queuelen += pbuf_clen(p).

src/api/api_lib.c

@@ -234,50 +234,6 @@ netbuf_first(struct netbuf *buf)
   buf->ptr = buf->p;
 }
 
-/**
- * Copy (part of) the contents of a packet buffer contained in a netbuf
- * to an application supplied buffer.
- *
- * @param buf the netbuf from which to copy data
- * @param dataptr the application supplied buffer
- * @param len length of data to copy (dataptr must be big enough)
- * @param offset offset into the packet buffer from where to begin copying len bytes
- */
-void
-netbuf_copy_partial(struct netbuf *buf, void *dataptr, u16_t len, u16_t offset)
-{
-  struct pbuf *p;
-  u16_t left;
-  u16_t buf_copy_len;
-
-  LWIP_ERROR("netbuf_copy_partial: invalid buf", (buf != NULL), return;);
-  LWIP_ERROR("netbuf_copy_partial: invalid dataptr", (dataptr != NULL), return;);
-
-  left = 0;
-
-  if(buf == NULL || dataptr == NULL) {
-    return;
-  }
-
-  /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
-  for(p = buf->p; len != 0 && p != NULL; p = p->next) {
-    if ((offset != 0) && (offset >= p->len)) {
-      /* don't copy from this buffer -> on to the next */
-      offset -= p->len;
-    } else {
-      /* copy from this buffer. maybe only partially. */
-      buf_copy_len = p->len - offset;
-      if (buf_copy_len > len)
-          buf_copy_len = len;
-      /* copy the necessary parts of the buffer */
-      MEMCPY(&((char*)dataptr)[left], &((char*)p->payload)[offset], buf_copy_len);
-      left += buf_copy_len;
-      len -= buf_copy_len;
-      offset = 0;
-    }
-  }
-}
-
 /**
  **********************************
  * Netconn functions

src/core/ipv4/ip_frag.c

@@ -59,40 +59,6 @@ static u8_t ip_reassflags;
 static u8_t ip_reasstmr;
 #endif /* IP_REASSEMBLY */
 
-#if IP_REASSEMBLY || (IP_FRAG && IP_FRAG_USES_STATIC_BUF)
-/*
- * Copy len bytes from offset in pbuf to buffer 
- *
- * helper used by both ip_reass and ip_frag
- *
- * @param p pbuf chain to copy from
- * @param offset offset in bytes into the pbuf chain which should be skipped
- *        before starting to copy
- * @param buffer destination to copy the data
- * @param len number of bytes to copy (starting from offset)
- * @return pointer to one pbuf in the chain p from which copied last
- */
-static struct pbuf *
-copy_from_pbuf(struct pbuf *p, u16_t *offset, u8_t *buffer, u16_t len)
-{
-  u16_t l;
-
-  p->payload = (u8_t *)p->payload + *offset;
-  p->len -= *offset;
-  while (len) {
-    l = len < p->len ? len : p->len;
-    MEMCPY(buffer, p->payload, l);
-    buffer += l;
-    len -= l;
-    if (len)
-      p = p->next;
-    else
-      *offset = l;
-  }
-  return p;
-}
-#endif /* IP_REASSEMBLY || IP_FRAG_USES_STATIC_BUF */
-
 #if IP_REASSEMBLY
 /**
  * Initializes IP reassembly states.
@@ -187,7 +153,7 @@ ip_reass(struct pbuf *p)
      ("ip_reass: copying with offset %"S16_F" into %"S16_F":%"S16_F"\n", offset,
       IP_HLEN + offset, IP_HLEN + offset + len));
     i = IPH_HL(fraghdr) * 4;
-    copy_from_pbuf(p, &i, &ip_reassbuf[IP_HLEN + offset], len);
+    pbuf_copy_partial(p, &ip_reassbuf[IP_HLEN + offset], len, i);
 
     /* Update the bitmap. */
     if (offset / (8 * 8) == (offset + len) / (8 * 8)) {
@@ -392,7 +358,7 @@ ip_frag(struct pbuf *p, struct netif *netif, struct ip_addr *dest)
     cop = last ? left : nfb * 8;
 
 #if IP_FRAG_USES_STATIC_BUF
-    p = copy_from_pbuf(p, &poff, (u8_t *) iphdr + IP_HLEN, cop);
+    poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
 #else /* IP_FRAG_USES_STATIC_BUF */
     /* When not using a static buffer, create a chain of pbufs.
      * The first will be a PBUF_RAM holding the link and IP header.

src/core/pbuf.c

@@ -735,3 +735,50 @@ pbuf_copy(struct pbuf *p_to, struct pbuf *p_from)
   LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE | 1, ("pbuf_copy: end of chain reached.\n"));
   return ERR_OK;
 }
+
+/**
+ * Copy (part of) the contents of a packet buffer
+ * to an application supplied buffer.
+ *
+ * @param buf the pbuf from which to copy data
+ * @param dataptr the application supplied buffer
+ * @param len length of data to copy (dataptr must be big enough)
+ * @param offset offset into the packet buffer from where to begin copying len bytes
+ */
+u16_t
+pbuf_copy_partial(struct pbuf *buf, void *dataptr, u16_t len, u16_t offset)
+{
+  struct pbuf *p;
+  u16_t left;
+  u16_t buf_copy_len;
+  u16_t copied_total = 0;
+
+  LWIP_ERROR("netbuf_copy_partial: invalid buf", (buf != NULL), return 0;);
+  LWIP_ERROR("netbuf_copy_partial: invalid dataptr", (dataptr != NULL), return 0;);
+
+  left = 0;
+
+  if((buf == NULL) || (dataptr == NULL)) {
+    return 0;
+  }
+
+  /* Note some systems use byte copy if dataptr or one of the pbuf payload pointers are unaligned. */
+  for(p = buf; len != 0 && p != NULL; p = p->next) {
+    if ((offset != 0) && (offset >= p->len)) {
+      /* don't copy from this buffer -> on to the next */
+      offset -= p->len;
+    } else {
+      /* copy from this buffer. maybe only partially. */
+      buf_copy_len = p->len - offset;
+      if (buf_copy_len > len)
+          buf_copy_len = len;
+      /* copy the necessary parts of the buffer */
+      MEMCPY(&((char*)dataptr)[left], &((char*)p->payload)[offset], buf_copy_len);
+      copied_total += buf_copy_len;
+      left += buf_copy_len;
+      len -= buf_copy_len;
+      offset = 0;
+    }
+  }
+  return copied_total;
+}

src/include/lwip/api.h

@@ -149,9 +149,9 @@ err_t             netbuf_data     (struct netbuf *buf,
 s8_t              netbuf_next     (struct netbuf *buf);
 void              netbuf_first    (struct netbuf *buf);
 
-void              netbuf_copy_partial(struct netbuf *buf, void *dataptr, 
-              u16_t len, u16_t offset);
 
+#define netbuf_copy_partial(buf, dataptr, len, offset) \
+  pbuf_copy_partial((buf)->p, (dataptr), (len), (offset))
 #define netbuf_copy(buf,dataptr,len) netbuf_copy_partial(buf, dataptr, len, 0)
 #define netbuf_len(buf)              ((buf)->p->tot_len)
 #define netbuf_fromaddr(buf)         ((buf)->addr)

src/include/lwip/pbuf.h

@@ -111,6 +111,7 @@ void pbuf_cat(struct pbuf *h, struct pbuf *t);
 void pbuf_chain(struct pbuf *h, struct pbuf *t);
 struct pbuf *pbuf_dechain(struct pbuf *p);
 err_t pbuf_copy(struct pbuf *p_to, struct pbuf *p_from);
+u16_t pbuf_copy_partial(struct pbuf *p, void *dataptr, u16_t len, u16_t offset);
 
 #ifdef __cplusplus
 }