int hh_len;
int exthdrlen;
int mtu;
- int copy;
+ int copy = 0;
int err;
int offset = 0;
- unsigned int maxfraglen, fragheaderlen;
+ unsigned int maxfraglen, fragheaderlen, fraggap = 0;
int csummode = CHECKSUM_NONE;
if (flags&MSG_PROBE)
hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
- maxfraglen = ((mtu-fragheaderlen) & ~7) + fragheaderlen;
if (inet->cork.length + length > 0xFFFF - fragheaderlen) {
ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu-exthdrlen);
return -EMSGSIZE;
}
+ /*
+ * Let's try using as much space as possible to avoid generating
+ * additional unnecessary small fragment of length
+ * (mtu-fragheaderlen)%8 if mtu-fragheaderlen is not 0 modulo 8.
+ * -- yoshfuji
+ */
+ if (fragheaderlen + inet->cork.length + length <= mtu)
+ maxfraglen = mtu;
+ else
+ maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
+
+ if (fragheaderlen + inet->cork.length <= mtu &&
+ fragheaderlen + inet->cork.length + length > mtu)
+ fraggap = 1;
+
/*
* transhdrlen > 0 means that this is the first fragment and we wish
* it won't be fragmented in the future.
* We use calculated fragment length to generate chained skb,
* each of segments is IP fragment ready for sending to network after
* adding appropriate IP header.
- *
- * Mistake is:
- *
- * If mtu-fragheaderlen is not 0 modulo 8, we generate additional
- * small fragment of length (mtu-fragheaderlen)%8, even though
- * it is not necessary. Not a big bug, but needs a fix.
*/
- if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
+ if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
+ fraggap = 0;
goto alloc_new_skb;
+ }
while (length > 0) {
if ((copy = maxfraglen - skb->len) <= 0) {
unsigned int datalen;
unsigned int fraglen;
unsigned int alloclen;
- BUG_TRAP(copy == 0);
+ struct sk_buff *skb_prev;
+ BUG_TRAP(fraggap || copy == 0);
alloc_new_skb:
+ skb_prev = skb;
+
+ if (fraggap)
+ fraggap = -copy;
+
datalen = maxfraglen - fragheaderlen;
- if (datalen > length)
- datalen = length;
+ if (datalen > length + fraggap)
+ datalen = length + fraggap;
fraglen = datalen + fragheaderlen;
if ((flags & MSG_MORE) &&
data += fragheaderlen;
skb->h.raw = data + exthdrlen;
- copy = datalen - transhdrlen;
+ if (fraggap) {
+ skb_copy_bits(skb_prev, maxfraglen,
+ data + transhdrlen, fraggap);
+ data += fraggap;
+ skb_trim(skb_prev, maxfraglen);
+ }
+
+ copy = datalen - transhdrlen - fraggap;
if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, 0, skb) < 0) {
err = -EFAULT;
kfree_skb(skb);
}
offset += copy;
- length -= datalen;
+ length -= datalen - fraggap;
transhdrlen = 0;
exthdrlen = 0;
+ fraggap = 0;
csummode = CHECKSUM_NONE;
/*
struct inet_opt *inet = inet_sk(sk);
struct ipv6_pinfo *np = inet6_sk(sk);
struct sk_buff *skb;
- unsigned int maxfraglen, fragheaderlen;
+ unsigned int maxfraglen, fragheaderlen, fraggap = 0;
int exthdrlen;
int hh_len;
int mtu;
hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
fragheaderlen = sizeof(struct ipv6hdr) + (opt ? opt->opt_nflen : 0);
- maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
}
}
+ /*
+ * Let's try using as much space as possible.
+ * Use MTU if total length of the message fits into the MTU.
+ * Otherwise, we need to reserve fragment header and
+ * fragment alignment (= 8-15 octects, in total).
+ *
+ * Note that we may need to "move" the data from the tail of
+ * of the buffer to the new fragment when we split
+ * the message at the first time.
+ *
+ * FIXME: It may be fragmented into multiple chunks
+ * at once if non-fragmentable extension headers
+ * are too large.
+ * --yoshfuji
+ */
+ if (fragheaderlen + inet->cork.length + length <= mtu)
+ maxfraglen = mtu;
+ else
+ maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen
+ - sizeof(struct frag_hdr);
+
+ if (fragheaderlen + inet->cork.length <= mtu &&
+ fragheaderlen + inet->cork.length + length > mtu)
+ fraggap = 1;
+
inet->cork.length += length;
- if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
+ if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
+ fraggap = 0;
goto alloc_new_skb;
+ }
while (length > 0) {
if ((copy = maxfraglen - skb->len) <= 0) {
unsigned int datalen;
unsigned int fraglen;
unsigned int alloclen;
- BUG_TRAP(copy == 0);
+ struct sk_buff *skb_prev;
+ BUG_TRAP(fraggap || copy == 0);
alloc_new_skb:
+ skb_prev = skb;
+
+ /* There's no room in the current skb */
+ if (fraggap)
+ fraggap = -copy;
+
datalen = maxfraglen - fragheaderlen;
- if (datalen > length)
- datalen = length;
+
+ if (datalen > length + fraggap)
+ datalen = length + fraggap;
+
fraglen = datalen + fragheaderlen;
if ((flags & MSG_MORE) &&
!(rt->u.dst.dev->features&NETIF_F_SG))
alloclen = maxfraglen;
else
- alloclen = fraglen;
+ alloclen = datalen + fragheaderlen;
+
+ /*
+ * The last fragment gets additional space at tail.
+ * Note: we overallocate on fragments with MSG_MODE
+ * because we have no idea if we're the last one.
+ */
+ if (datalen == length + fraggap)
+ alloclen += rt->u.dst.trailer_len;
+
+ /*
+ * We just reserve space for fragment header.
+ * Note: this may be overallocation if the message
+ * (without MSG_MORE) fits into the MTU.
+ */
alloclen += sizeof(struct frag_hdr);
+
if (transhdrlen) {
skb = sock_alloc_send_skb(sk,
alloclen + hh_len,
*/
skb->ip_summed = csummode;
skb->csum = 0;
- /* reserve 8 byte for fragmentation */
+ /* reserve for fragmentation */
skb_reserve(skb, hh_len+sizeof(struct frag_hdr));
/*
skb->nh.raw = data + exthdrlen;
data += fragheaderlen;
skb->h.raw = data + exthdrlen;
- copy = datalen - transhdrlen;
- if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, 0, skb) < 0) {
+
+ if (fraggap) {
+ skb_copy_bits(skb_prev, maxfraglen,
+ data + transhdrlen, fraggap);
+ data += fraggap;
+ skb_trim(skb_prev, maxfraglen);
+ }
+ copy = datalen - transhdrlen - fraggap;
+ if (copy < 0) {
+ err = -EINVAL;
+ kfree_skb(skb);
+ goto error;
+ } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, 0, skb) < 0) {
err = -EFAULT;
kfree_skb(skb);
goto error;
}
offset += copy;
- length -= datalen;
+ length -= datalen - fraggap;
transhdrlen = 0;
exthdrlen = 0;
+ fraggap = 0;
csummode = CHECKSUM_NONE;
/*
projects / linux / commitdiff