Just noticed a typo in the commit msg, refacored != refactored. I'll fix in v5
after further comments.
- Martin.
On 16/09/14 12:01, Martin Townsend wrote:
> Currently there are a number of error paths in the lowpan_rcv function that
> free the skb before returning, the patch simplifies the receive path by
> ensuring that the skb is only freed from this function.
>
> Passing the skb from 6lowpan up to the higher layers is not a
> function of IPHC. By moving it out of IPHC we also remove the
> need to support error code returns with NET_RX codes.
> It also makes the lowpan_rcv function more extendable as we
> can support more compression schemes.
>
> With the above 2 lowpan_rcv is refacored so eliminate incorrect return values.
>
> Signed-off-by: Martin Townsend <martin.towns...@xsilon.com>
> ---
> include/net/6lowpan.h | 9 +++--
> net/6lowpan/iphc.c | 88
> +++++++++++++++++--------------------------
> net/bluetooth/6lowpan.c | 38 ++++++++++---------
> net/ieee802154/6lowpan_rtnl.c | 61 ++++++++++++++++--------------
> 4 files changed, 94 insertions(+), 102 deletions(-)
>
> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
> index d184df1..c28fadb 100644
> --- a/include/net/6lowpan.h
> +++ b/include/net/6lowpan.h
> @@ -374,10 +374,11 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16
> *dgram_offset)
>
> typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
>
> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> - const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
> - const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
> - u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
> +struct sk_buff *
> +lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> + const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
> + const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
> + u8 iphc0, u8 iphc1);
> int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
> unsigned short type, const void *_daddr,
> const void *_saddr, unsigned int len);
> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
> index 142eef5..6ac7765 100644
> --- a/net/6lowpan/iphc.c
> +++ b/net/6lowpan/iphc.c
> @@ -171,37 +171,6 @@ static int uncompress_context_based_src_addr(struct
> sk_buff *skb,
> return 0;
> }
>
> -static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
> - struct net_device *dev, skb_delivery_cb deliver_skb)
> -{
> - struct sk_buff *new;
> - int stat;
> -
> - new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
> - GFP_ATOMIC);
> - kfree_skb(skb);
> -
> - if (!new)
> - return -ENOMEM;
> -
> - skb_push(new, sizeof(struct ipv6hdr));
> - skb_reset_network_header(new);
> - skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
> -
> - new->protocol = htons(ETH_P_IPV6);
> - new->pkt_type = PACKET_HOST;
> - new->dev = dev;
> -
> - raw_dump_table(__func__, "raw skb data dump before receiving",
> - new->data, new->len);
> -
> - stat = deliver_skb(new, dev);
> -
> - kfree_skb(new);
> -
> - return stat;
> -}
> -
> /* Uncompress function for multicast destination address,
> * when M bit is set.
> */
> @@ -332,14 +301,16 @@ err:
> /* TTL uncompression values */
> static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
>
> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> - const u8 *saddr, const u8 saddr_type, const u8
> saddr_len,
> - const u8 *daddr, const u8 daddr_type, const u8
> daddr_len,
> - u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
> +struct sk_buff *
> +lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> + const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
> + const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
> + u8 iphc0, u8 iphc1)
> {
> struct ipv6hdr hdr = {};
> u8 tmp, num_context = 0;
> int err;
> + struct sk_buff *new;
>
> raw_dump_table(__func__, "raw skb data dump uncompressed",
> skb->data, skb->len);
> @@ -348,7 +319,7 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
> if (iphc1 & LOWPAN_IPHC_CID) {
> pr_debug("CID flag is set, increase header with one\n");
> if (lowpan_fetch_skb(skb, &num_context, sizeof(num_context)))
> - goto drop;
> + return ERR_PTR(-EINVAL);
> }
>
> hdr.version = 6;
> @@ -360,7 +331,7 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
> */
> case 0: /* 00b */
> if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> memcpy(&hdr.flow_lbl, &skb->data[0], 3);
> skb_pull(skb, 3);
> @@ -373,7 +344,7 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
> */
> case 2: /* 10b */
> if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> hdr.priority = ((tmp >> 2) & 0x0f);
> hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
> @@ -383,7 +354,7 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
> */
> case 1: /* 01b */
> if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30);
> memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
> @@ -400,7 +371,7 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
> if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
> /* Next header is carried inline */
> if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> pr_debug("NH flag is set, next header carried inline: %02x\n",
> hdr.nexthdr);
> @@ -412,7 +383,7 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
> } else {
> if (lowpan_fetch_skb(skb, &hdr.hop_limit,
> sizeof(hdr.hop_limit)))
> - goto drop;
> + return ERR_PTR(-EINVAL);
> }
>
> /* Extract SAM to the tmp variable */
> @@ -431,7 +402,7 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
>
> /* Check on error of previous branch */
> if (err)
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> /* Extract DAM to the tmp variable */
> tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
> @@ -446,7 +417,7 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
> tmp);
>
> if (err)
> - goto drop;
> + return ERR_PTR(-EINVAL);
> }
> } else {
> err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
> @@ -454,27 +425,25 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
> pr_debug("dest: stateless compression mode %d dest %pI6c\n",
> tmp, &hdr.daddr);
> if (err)
> - goto drop;
> + return ERR_PTR(-EINVAL);
> }
>
> /* UDP data uncompression */
> if (iphc0 & LOWPAN_IPHC_NH_C) {
> struct udphdr uh;
> - struct sk_buff *new;
>
> if (uncompress_udp_header(skb, &uh))
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> /* replace the compressed UDP head by the uncompressed UDP
> * header
> */
> new = skb_copy_expand(skb, sizeof(struct udphdr),
> skb_tailroom(skb), GFP_ATOMIC);
> - kfree_skb(skb);
> -
> if (!new)
> - return -ENOMEM;
> + return ERR_PTR(-ENOMEM);
>
> + consume_skb(skb);
> skb = new;
>
> skb_push(skb, sizeof(struct udphdr));
> @@ -499,11 +468,24 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
>
> raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
>
> - return skb_deliver(skb, &hdr, dev, deliver_skb);
> + /* Setup skb with new uncompressed IPv6 header. */
> + new = skb_copy_expand(skb, sizeof(hdr), skb_tailroom(skb),
> + GFP_ATOMIC);
> + if (!new)
> + return ERR_PTR(-ENOMEM);
>
> -drop:
> - kfree_skb(skb);
> - return -EINVAL;
> + consume_skb(skb);
> + skb = new;
> +
> + skb_push(skb, sizeof(hdr));
> + skb_reset_network_header(skb);
> + skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
> + skb->dev = dev;
> +
> + raw_dump_table(__func__, "raw skb data dump before receiving",
> + skb->data, skb->len);
> +
> + return skb;
> }
> EXPORT_SYMBOL_GPL(lowpan_process_data);
>
> diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
> index 206b65c..a44938b 100644
> --- a/net/bluetooth/6lowpan.c
> +++ b/net/bluetooth/6lowpan.c
> @@ -215,8 +215,9 @@ static int give_skb_to_upper(struct sk_buff *skb, struct
> net_device *dev)
> return ret;
> }
>
> -static int process_data(struct sk_buff *skb, struct net_device *netdev,
> - struct l2cap_chan *chan)
> +static struct sk_buff *
> +process_data(struct sk_buff *skb, struct net_device *netdev,
> + struct l2cap_chan *chan)
> {
> const u8 *saddr, *daddr;
> u8 iphc0, iphc1;
> @@ -230,36 +231,31 @@ static int process_data(struct sk_buff *skb, struct
> net_device *netdev,
> peer = peer_lookup_chan(dev, chan);
> read_unlock_irqrestore(&devices_lock, flags);
> if (!peer)
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> saddr = peer->eui64_addr;
> daddr = dev->netdev->dev_addr;
>
> /* at least two bytes will be used for the encoding */
> if (skb->len < 2)
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> if (lowpan_fetch_skb_u8(skb, &iphc0))
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> if (lowpan_fetch_skb_u8(skb, &iphc1))
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> return lowpan_process_data(skb, netdev,
> saddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
> daddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
> - iphc0, iphc1, give_skb_to_upper);
> -
> -drop:
> - kfree_skb(skb);
> - return -EINVAL;
> + iphc0, iphc1);
> }
>
> static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
> struct l2cap_chan *chan)
> {
> struct sk_buff *local_skb;
> - int ret;
>
> if (!netif_running(dev))
> goto drop;
> @@ -280,9 +276,6 @@ static int recv_pkt(struct sk_buff *skb, struct
> net_device *dev,
> local_skb->protocol = htons(ETH_P_IPV6);
> local_skb->pkt_type = PACKET_HOST;
>
> - skb_reset_network_header(local_skb);
> - skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
> -
> if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
> kfree_skb(local_skb);
> goto drop;
> @@ -300,9 +293,20 @@ static int recv_pkt(struct sk_buff *skb, struct
> net_device *dev,
> if (!local_skb)
> goto drop;
>
> - ret = process_data(local_skb, dev, chan);
> - if (ret != NET_RX_SUCCESS)
> + skb = process_data(local_skb, dev, chan);
> + if (IS_ERR(skb)) {
> + kfree_skb(local_skb);
> goto drop;
> + }
> +
> + local_skb->protocol = htons(ETH_P_IPV6);
> + local_skb->pkt_type = PACKET_HOST;
> +
> + if (give_skb_to_upper(local_skb, dev)
> + != NET_RX_SUCCESS) {
> + kfree_skb(local_skb);
> + goto drop;
> + }
>
> dev->stats.rx_bytes += skb->len;
> dev->stats.rx_packets++;
> diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
> index 6591d27..a0804df 100644
> --- a/net/ieee802154/6lowpan_rtnl.c
> +++ b/net/ieee802154/6lowpan_rtnl.c
> @@ -155,8 +155,9 @@ static int lowpan_give_skb_to_devices(struct sk_buff *skb,
> if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
> skb_cp = skb_copy(skb, GFP_ATOMIC);
> if (!skb_cp) {
> - stat = -ENOMEM;
> - break;
> + kfree_skb(skb);
> + rcu_read_unlock();
> + return NET_RX_DROP;
> }
>
> skb_cp->dev = entry->ldev;
> @@ -164,10 +165,13 @@ static int lowpan_give_skb_to_devices(struct sk_buff
> *skb,
> }
> rcu_read_unlock();
>
> + consume_skb(skb);
> +
> return stat;
> }
>
> -static int process_data(struct sk_buff *skb, const struct ieee802154_hdr
> *hdr)
> +static struct sk_buff *
> +process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
> {
> u8 iphc0, iphc1;
> struct ieee802154_addr_sa sa, da;
> @@ -176,13 +180,13 @@ static int process_data(struct sk_buff *skb, const
> struct ieee802154_hdr *hdr)
> raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
> /* at least two bytes will be used for the encoding */
> if (skb->len < 2)
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> if (lowpan_fetch_skb_u8(skb, &iphc0))
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> if (lowpan_fetch_skb_u8(skb, &iphc1))
> - goto drop;
> + return ERR_PTR(-EINVAL);
>
> ieee802154_addr_to_sa(&sa, &hdr->source);
> ieee802154_addr_to_sa(&da, &hdr->dest);
> @@ -199,12 +203,7 @@ static int process_data(struct sk_buff *skb, const
> struct ieee802154_hdr *hdr)
>
> return lowpan_process_data(skb, skb->dev, sap, sa.addr_type,
> IEEE802154_ADDR_LEN, dap, da.addr_type,
> - IEEE802154_ADDR_LEN, iphc0, iphc1,
> - lowpan_give_skb_to_devices);
> -
> -drop:
> - kfree_skb(skb);
> - return -EINVAL;
> + IEEE802154_ADDR_LEN, iphc0, iphc1);
> }
>
> static int lowpan_set_address(struct net_device *dev, void *p)
> @@ -478,36 +477,38 @@ static int lowpan_rcv(struct sk_buff *skb, struct
> net_device *dev,
>
> /* check that it's our buffer */
> if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
> - skb->protocol = htons(ETH_P_IPV6);
> - skb->pkt_type = PACKET_HOST;
> -
> /* Pull off the 1-byte of 6lowpan header. */
> skb_pull(skb, 1);
>
> - ret = lowpan_give_skb_to_devices(skb, NULL);
> - if (ret == NET_RX_DROP)
> - goto drop;
> } else {
> switch (skb->data[0] & 0xe0) {
> case LOWPAN_DISPATCH_IPHC: /* ipv6 datagram */
> - ret = process_data(skb, &hdr);
> - if (ret == NET_RX_DROP)
> - goto drop;
> + skb = process_data(skb, &hdr);
> + if (IS_ERR(skb))
> + goto drop_skb;
> break;
> case LOWPAN_DISPATCH_FRAG1: /* first fragment header */
> ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
> if (ret == 1) {
> - ret = process_data(skb, &hdr);
> - if (ret == NET_RX_DROP)
> - goto drop;
> + skb = process_data(skb, &hdr);
> + if (IS_ERR(skb))
> + goto drop_skb;
> + } else if (ret < 0) {
> + goto drop;
> + } else {
> + return NET_RX_SUCCESS;
> }
> break;
> case LOWPAN_DISPATCH_FRAGN: /* next fragments headers */
> ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
> if (ret == 1) {
> - ret = process_data(skb, &hdr);
> - if (ret == NET_RX_DROP)
> - goto drop;
> + skb = process_data(skb, &hdr);
> + if (IS_ERR(skb))
> + goto drop_skb;
> + } else if (ret < 0) {
> + goto drop;
> + } else {
> + return NET_RX_SUCCESS;
> }
> break;
> default:
> @@ -515,7 +516,11 @@ static int lowpan_rcv(struct sk_buff *skb, struct
> net_device *dev,
> }
> }
>
> - return NET_RX_SUCCESS;
> + /* Pass IPv6 packet up to next layer */
> + skb->protocol = htons(ETH_P_IPV6);
> + skb->pkt_type = PACKET_HOST;
> + return lowpan_give_skb_to_devices(skb, NULL);
> +
> drop_skb:
> kfree_skb(skb);
> drop:
------------------------------------------------------------------------------
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