315 lines
8.5 KiB
C
315 lines
8.5 KiB
C
/* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <net/6lowpan.h>
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#include <net/ndisc.h>
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#include <net/ieee802154_netdev.h>
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#include <net/mac802154.h>
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#include "6lowpan_i.h"
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#define LOWPAN_FRAG1_HEAD_SIZE 0x4
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#define LOWPAN_FRAGN_HEAD_SIZE 0x5
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struct lowpan_addr_info {
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struct ieee802154_addr daddr;
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struct ieee802154_addr saddr;
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};
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static inline struct
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lowpan_addr_info *lowpan_skb_priv(const struct sk_buff *skb)
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{
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WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct lowpan_addr_info));
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return (struct lowpan_addr_info *)(skb->data -
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sizeof(struct lowpan_addr_info));
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}
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/* This callback will be called from AF_PACKET and IPv6 stack, the AF_PACKET
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* sockets gives an 8 byte array for addresses only!
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*
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* TODO I think AF_PACKET DGRAM (sending/receiving) RAW (sending) makes no
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* sense here. We should disable it, the right use-case would be AF_INET6
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* RAW/DGRAM sockets.
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*/
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int lowpan_header_create(struct sk_buff *skb, struct net_device *ldev,
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unsigned short type, const void *daddr,
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const void *saddr, unsigned int len)
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{
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struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr;
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struct lowpan_addr_info *info = lowpan_skb_priv(skb);
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struct lowpan_802154_neigh *llneigh = NULL;
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const struct ipv6hdr *hdr = ipv6_hdr(skb);
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struct neighbour *n;
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/* TODO:
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* if this package isn't ipv6 one, where should it be routed?
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*/
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if (type != ETH_P_IPV6)
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return 0;
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/* intra-pan communication */
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info->saddr.pan_id = wpan_dev->pan_id;
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info->daddr.pan_id = info->saddr.pan_id;
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if (!memcmp(daddr, ldev->broadcast, EUI64_ADDR_LEN)) {
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info->daddr.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
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info->daddr.mode = IEEE802154_ADDR_SHORT;
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} else {
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__le16 short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
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n = neigh_lookup(&nd_tbl, &hdr->daddr, ldev);
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if (n) {
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llneigh = lowpan_802154_neigh(neighbour_priv(n));
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read_lock_bh(&n->lock);
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short_addr = llneigh->short_addr;
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read_unlock_bh(&n->lock);
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}
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if (llneigh &&
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lowpan_802154_is_valid_src_short_addr(short_addr)) {
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info->daddr.short_addr = short_addr;
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info->daddr.mode = IEEE802154_ADDR_SHORT;
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} else {
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info->daddr.mode = IEEE802154_ADDR_LONG;
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ieee802154_be64_to_le64(&info->daddr.extended_addr,
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daddr);
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}
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if (n)
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neigh_release(n);
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}
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if (!saddr) {
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if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr)) {
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info->saddr.mode = IEEE802154_ADDR_SHORT;
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info->saddr.short_addr = wpan_dev->short_addr;
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} else {
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info->saddr.mode = IEEE802154_ADDR_LONG;
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info->saddr.extended_addr = wpan_dev->extended_addr;
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}
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} else {
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info->saddr.mode = IEEE802154_ADDR_LONG;
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ieee802154_be64_to_le64(&info->saddr.extended_addr, saddr);
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}
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return 0;
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}
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static struct sk_buff*
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lowpan_alloc_frag(struct sk_buff *skb, int size,
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const struct ieee802154_hdr *master_hdr, bool frag1)
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{
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struct net_device *wdev = lowpan_802154_dev(skb->dev)->wdev;
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struct sk_buff *frag;
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int rc;
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frag = alloc_skb(wdev->needed_headroom + wdev->needed_tailroom + size,
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GFP_ATOMIC);
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if (likely(frag)) {
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frag->dev = wdev;
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frag->priority = skb->priority;
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skb_reserve(frag, wdev->needed_headroom);
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skb_reset_network_header(frag);
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*mac_cb(frag) = *mac_cb(skb);
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if (frag1) {
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skb_put_data(frag, skb_mac_header(skb), skb->mac_len);
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} else {
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rc = wpan_dev_hard_header(frag, wdev,
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&master_hdr->dest,
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&master_hdr->source, size);
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if (rc < 0) {
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kfree_skb(frag);
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return ERR_PTR(rc);
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}
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}
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} else {
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frag = ERR_PTR(-ENOMEM);
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}
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return frag;
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}
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static int
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lowpan_xmit_fragment(struct sk_buff *skb, const struct ieee802154_hdr *wpan_hdr,
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u8 *frag_hdr, int frag_hdrlen,
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int offset, int len, bool frag1)
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{
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struct sk_buff *frag;
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raw_dump_inline(__func__, " fragment header", frag_hdr, frag_hdrlen);
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frag = lowpan_alloc_frag(skb, frag_hdrlen + len, wpan_hdr, frag1);
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if (IS_ERR(frag))
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return PTR_ERR(frag);
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skb_put_data(frag, frag_hdr, frag_hdrlen);
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skb_put_data(frag, skb_network_header(skb) + offset, len);
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raw_dump_table(__func__, " fragment dump", frag->data, frag->len);
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return dev_queue_xmit(frag);
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}
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static int
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lowpan_xmit_fragmented(struct sk_buff *skb, struct net_device *ldev,
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const struct ieee802154_hdr *wpan_hdr, u16 dgram_size,
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u16 dgram_offset)
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{
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__be16 frag_tag;
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u8 frag_hdr[5];
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int frag_cap, frag_len, payload_cap, rc;
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int skb_unprocessed, skb_offset;
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frag_tag = htons(lowpan_802154_dev(ldev)->fragment_tag);
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lowpan_802154_dev(ldev)->fragment_tag++;
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frag_hdr[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x07);
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frag_hdr[1] = dgram_size & 0xff;
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memcpy(frag_hdr + 2, &frag_tag, sizeof(frag_tag));
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payload_cap = ieee802154_max_payload(wpan_hdr);
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frag_len = round_down(payload_cap - LOWPAN_FRAG1_HEAD_SIZE -
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skb_network_header_len(skb), 8);
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skb_offset = skb_network_header_len(skb);
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skb_unprocessed = skb->len - skb->mac_len - skb_offset;
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rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
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LOWPAN_FRAG1_HEAD_SIZE, 0,
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frag_len + skb_network_header_len(skb),
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true);
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if (rc) {
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pr_debug("%s unable to send FRAG1 packet (tag: %d)",
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__func__, ntohs(frag_tag));
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goto err;
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}
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frag_hdr[0] &= ~LOWPAN_DISPATCH_FRAG1;
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frag_hdr[0] |= LOWPAN_DISPATCH_FRAGN;
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frag_cap = round_down(payload_cap - LOWPAN_FRAGN_HEAD_SIZE, 8);
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do {
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dgram_offset += frag_len;
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skb_offset += frag_len;
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skb_unprocessed -= frag_len;
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frag_len = min(frag_cap, skb_unprocessed);
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frag_hdr[4] = dgram_offset >> 3;
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rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
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LOWPAN_FRAGN_HEAD_SIZE, skb_offset,
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frag_len, false);
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if (rc) {
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pr_debug("%s unable to send a FRAGN packet. (tag: %d, offset: %d)\n",
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__func__, ntohs(frag_tag), skb_offset);
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goto err;
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}
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} while (skb_unprocessed > frag_cap);
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ldev->stats.tx_packets++;
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ldev->stats.tx_bytes += dgram_size;
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consume_skb(skb);
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return NET_XMIT_SUCCESS;
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err:
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kfree_skb(skb);
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return rc;
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}
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static int lowpan_header(struct sk_buff *skb, struct net_device *ldev,
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u16 *dgram_size, u16 *dgram_offset)
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{
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struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr;
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struct ieee802154_mac_cb *cb = mac_cb_init(skb);
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struct lowpan_addr_info info;
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memcpy(&info, lowpan_skb_priv(skb), sizeof(info));
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*dgram_size = skb->len;
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lowpan_header_compress(skb, ldev, &info.daddr, &info.saddr);
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/* dgram_offset = (saved bytes after compression) + lowpan header len */
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*dgram_offset = (*dgram_size - skb->len) + skb_network_header_len(skb);
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cb->type = IEEE802154_FC_TYPE_DATA;
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if (info.daddr.mode == IEEE802154_ADDR_SHORT &&
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ieee802154_is_broadcast_short_addr(info.daddr.short_addr))
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cb->ackreq = false;
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else
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cb->ackreq = wpan_dev->ackreq;
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return wpan_dev_hard_header(skb, lowpan_802154_dev(ldev)->wdev,
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&info.daddr, &info.saddr, 0);
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}
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netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev)
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{
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struct ieee802154_hdr wpan_hdr;
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int max_single, ret;
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u16 dgram_size, dgram_offset;
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pr_debug("package xmit\n");
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WARN_ON_ONCE(skb->len > IPV6_MIN_MTU);
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/* We must take a copy of the skb before we modify/replace the ipv6
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* header as the header could be used elsewhere
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*/
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if (unlikely(skb_headroom(skb) < ldev->needed_headroom ||
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skb_tailroom(skb) < ldev->needed_tailroom)) {
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struct sk_buff *nskb;
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nskb = skb_copy_expand(skb, ldev->needed_headroom,
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ldev->needed_tailroom, GFP_ATOMIC);
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if (likely(nskb)) {
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consume_skb(skb);
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skb = nskb;
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} else {
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kfree_skb(skb);
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return NET_XMIT_DROP;
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}
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} else {
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skb = skb_unshare(skb, GFP_ATOMIC);
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if (!skb)
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return NET_XMIT_DROP;
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}
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ret = lowpan_header(skb, ldev, &dgram_size, &dgram_offset);
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if (ret < 0) {
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kfree_skb(skb);
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return NET_XMIT_DROP;
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}
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if (ieee802154_hdr_peek(skb, &wpan_hdr) < 0) {
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kfree_skb(skb);
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return NET_XMIT_DROP;
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}
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max_single = ieee802154_max_payload(&wpan_hdr);
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if (skb_tail_pointer(skb) - skb_network_header(skb) <= max_single) {
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skb->dev = lowpan_802154_dev(ldev)->wdev;
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ldev->stats.tx_packets++;
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ldev->stats.tx_bytes += dgram_size;
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return dev_queue_xmit(skb);
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} else {
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netdev_tx_t rc;
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pr_debug("frame is too big, fragmentation is needed\n");
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rc = lowpan_xmit_fragmented(skb, ldev, &wpan_hdr, dgram_size,
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dgram_offset);
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return rc < 0 ? NET_XMIT_DROP : rc;
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}
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}
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