diff options
Diffstat (limited to 'net/ipv4/ip_output.c')
| -rw-r--r-- | net/ipv4/ip_output.c | 200 |
1 files changed, 112 insertions, 88 deletions
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index d03eb4ae0dd4..c3f139843eca 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -609,6 +609,111 @@ void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter) } EXPORT_SYMBOL(ip_fraglist_prepare); +void ip_frag_init(struct sk_buff *skb, unsigned int hlen, + unsigned int ll_rs, unsigned int mtu, + struct ip_frag_state *state) +{ + struct iphdr *iph = ip_hdr(skb); + + state->hlen = hlen; + state->ll_rs = ll_rs; + state->mtu = mtu; + + state->left = skb->len - hlen; /* Space per frame */ + state->ptr = hlen; /* Where to start from */ + + state->offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; + state->not_last_frag = iph->frag_off & htons(IP_MF); +} +EXPORT_SYMBOL(ip_frag_init); + +struct sk_buff *ip_frag_next(struct sk_buff *skb, struct ip_frag_state *state) +{ + unsigned int len = state->left; + struct sk_buff *skb2; + struct iphdr *iph; + + len = state->left; + /* IF: it doesn't fit, use 'mtu' - the data space left */ + if (len > state->mtu) + len = state->mtu; + /* IF: we are not sending up to and including the packet end + then align the next start on an eight byte boundary */ + if (len < state->left) { + len &= ~7; + } + + /* Allocate buffer */ + skb2 = alloc_skb(len + state->hlen + state->ll_rs, GFP_ATOMIC); + if (!skb2) + return ERR_PTR(-ENOMEM); + + /* + * Set up data on packet + */ + + ip_copy_metadata(skb2, skb); + skb_reserve(skb2, state->ll_rs); + skb_put(skb2, len + state->hlen); + skb_reset_network_header(skb2); + skb2->transport_header = skb2->network_header + state->hlen; + + /* + * Charge the memory for the fragment to any owner + * it might possess + */ + + if (skb->sk) + skb_set_owner_w(skb2, skb->sk); + + /* + * Copy the packet header into the new buffer. + */ + + skb_copy_from_linear_data(skb, skb_network_header(skb2), state->hlen); + + /* + * Copy a block of the IP datagram. + */ + if (skb_copy_bits(skb, state->ptr, skb_transport_header(skb2), len)) + BUG(); + state->left -= len; + + /* + * Fill in the new header fields. + */ + iph = ip_hdr(skb2); + iph->frag_off = htons((state->offset >> 3)); + + if (IPCB(skb)->flags & IPSKB_FRAG_PMTU) + iph->frag_off |= htons(IP_DF); + + /* ANK: dirty, but effective trick. Upgrade options only if + * the segment to be fragmented was THE FIRST (otherwise, + * options are already fixed) and make it ONCE + * on the initial skb, so that all the following fragments + * will inherit fixed options. + */ + if (state->offset == 0) + ip_options_fragment(skb); + + /* + * Added AC : If we are fragmenting a fragment that's not the + * last fragment then keep MF on each bit + */ + if (state->left > 0 || state->not_last_frag) + iph->frag_off |= htons(IP_MF); + state->ptr += len; + state->offset += len; + + iph->tot_len = htons(len + state->hlen); + + ip_send_check(iph); + + return skb2; +} +EXPORT_SYMBOL(ip_frag_next); + /* * This IP datagram is too large to be sent in one piece. Break it up into * smaller pieces (each of size equal to IP header plus @@ -620,13 +725,11 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, int (*output)(struct net *, struct sock *, struct sk_buff *)) { struct iphdr *iph; - int ptr; struct sk_buff *skb2; - unsigned int mtu, hlen, left, len, ll_rs; - int offset; - __be16 not_last_frag; struct rtable *rt = skb_rtable(skb); + unsigned int mtu, hlen, ll_rs; struct ip_fraglist_iter iter; + struct ip_frag_state state; int err = 0; /* for offloaded checksums cleanup checksum before fragmentation */ @@ -730,105 +833,26 @@ slow_path_clean: } slow_path: - iph = ip_hdr(skb); - - left = skb->len - hlen; /* Space per frame */ - ptr = hlen; /* Where to start from */ - /* * Fragment the datagram. */ - offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; - not_last_frag = iph->frag_off & htons(IP_MF); + ip_frag_init(skb, hlen, ll_rs, mtu, &state); /* * Keep copying data until we run out. */ - while (left > 0) { - len = left; - /* IF: it doesn't fit, use 'mtu' - the data space left */ - if (len > mtu) - len = mtu; - /* IF: we are not sending up to and including the packet end - then align the next start on an eight byte boundary */ - if (len < left) { - len &= ~7; - } - - /* Allocate buffer */ - skb2 = alloc_skb(len + hlen + ll_rs, GFP_ATOMIC); - if (!skb2) { - err = -ENOMEM; + while (state.left > 0) { + skb2 = ip_frag_next(skb, &state); + if (IS_ERR(skb2)) { + err = PTR_ERR(skb2); goto fail; } /* - * Set up data on packet - */ - - ip_copy_metadata(skb2, skb); - skb_reserve(skb2, ll_rs); - skb_put(skb2, len + hlen); - skb_reset_network_header(skb2); - skb2->transport_header = skb2->network_header + hlen; - - /* - * Charge the memory for the fragment to any owner - * it might possess - */ - - if (skb->sk) - skb_set_owner_w(skb2, skb->sk); - - /* - * Copy the packet header into the new buffer. - */ - - skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen); - - /* - * Copy a block of the IP datagram. - */ - if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len)) - BUG(); - left -= len; - - /* - * Fill in the new header fields. - */ - iph = ip_hdr(skb2); - iph->frag_off = htons((offset >> 3)); - - if (IPCB(skb)->flags & IPSKB_FRAG_PMTU) - iph->frag_off |= htons(IP_DF); - - /* ANK: dirty, but effective trick. Upgrade options only if - * the segment to be fragmented was THE FIRST (otherwise, - * options are already fixed) and make it ONCE - * on the initial skb, so that all the following fragments - * will inherit fixed options. - */ - if (offset == 0) - ip_options_fragment(skb); - - /* - * Added AC : If we are fragmenting a fragment that's not the - * last fragment then keep MF on each bit - */ - if (left > 0 || not_last_frag) - iph->frag_off |= htons(IP_MF); - ptr += len; - offset += len; - - /* * Put this fragment into the sending queue. */ - iph->tot_len = htons(len + hlen); - - ip_send_check(iph); - err = output(net, sk, skb2); if (err) goto fail; |