Hi Martin,
something is wrong with you mail client. I received the cover letter
twice one has some wrong reply-to id. Please check this.
Do you use git send-email? How, maybe we can help you there.
On Fri, Sep 12, 2014 at 10:34:40AM +0100, 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.townsend@xxxxxxxxxx>
> ---
> include/net/6lowpan.h | 4 +--
> net/6lowpan/iphc.c | 73 ++++++++++++++++++-------------------------
> net/bluetooth/6lowpan.c | 26 +++++++++------
> net/ieee802154/6lowpan_rtnl.c | 44 +++++++++++++++-----------
> 4 files changed, 75 insertions(+), 72 deletions(-)
>
> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
> index d184df1..450eaaf 100644
> --- a/include/net/6lowpan.h
> +++ b/include/net/6lowpan.h
> @@ -374,10 +374,10 @@ 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,
> +int lowpan_process_data(struct sk_buff **skb_inout, 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);
> + u8 iphc0, u8 iphc1);
check checkpatch here.
CHECK: Alignment should match open parenthesis
#37: FILE: include/net/6lowpan.h:378:
+int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
> 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..43ed1b4 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,
> +int lowpan_process_data(struct sk_buff **skb_inout, 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)
> + u8 iphc0, u8 iphc1)
> {
> struct ipv6hdr hdr = {};
> u8 tmp, num_context = 0;
> int err;
> + int err_ret = -EINVAL;
use err here, I saw this in your cover-letter as change but it's not
really changed.
> + struct sk_buff *skb = *skb_inout;
>
> raw_dump_table(__func__, "raw skb data dump uncompressed",
> skb->data, skb->len);
> @@ -460,7 +431,6 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> /* UDP data uncompression */
> if (iphc0 & LOWPAN_IPHC_NH_C) {
> struct udphdr uh;
> - struct sk_buff *new;
>
> if (uncompress_udp_header(skb, &uh))
> goto drop;
> @@ -468,14 +438,15 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> /* replace the compressed UDP head by the uncompressed UDP
> * header
> */
> - new = skb_copy_expand(skb, sizeof(struct udphdr),
> + skb = skb_copy_expand(skb, sizeof(struct udphdr),
> skb_tailroom(skb), GFP_ATOMIC);
> - kfree_skb(skb);
> -
> - if (!new)
> - return -ENOMEM;
> + if (!skb) {
> + err_ret = -ENOMEM;
> + goto drop;
> + }
>
> - skb = new;
> + kfree_skb(*skb_inout);
> + *skb_inout = skb;
>
> skb_push(skb, sizeof(struct udphdr));
> skb_reset_transport_header(skb);
> @@ -499,11 +470,27 @@ 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. */
> + skb = skb_copy_expand(skb, sizeof(hdr), skb_tailroom(skb),
> + GFP_ATOMIC);
> + if (!skb)
> + return -ENOMEM;
> +
> + kfree_skb(*skb_inout);
> + *skb_inout = skb;
> +
> + 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 0;
>
> drop:
> - kfree_skb(skb);
> - return -EINVAL;
> + return err_ret;
> }
> EXPORT_SYMBOL_GPL(lowpan_process_data);
>
> diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
> index 206b65c..a4e340e 100644
> --- a/net/bluetooth/6lowpan.c
> +++ b/net/bluetooth/6lowpan.c
> @@ -215,7 +215,7 @@ 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,
> +static int process_data(struct sk_buff **skb_inout, struct net_device *netdev,
> struct l2cap_chan *chan)
> {
> const u8 *saddr, *daddr;
> @@ -223,6 +223,7 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
> struct lowpan_dev *dev;
> struct lowpan_peer *peer;
> unsigned long flags;
> + struct sk_buff *skb = *skb_inout;
>
> dev = lowpan_dev(netdev);
>
> @@ -245,13 +246,12 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
> if (lowpan_fetch_skb_u8(skb, &iphc1))
> goto drop;
>
> - return lowpan_process_data(skb, netdev,
> + return lowpan_process_data(skb_inout, netdev,
> saddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
> daddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
> - iphc0, iphc1, give_skb_to_upper);
> + iphc0, iphc1);
>
> drop:
> - kfree_skb(skb);
> return -EINVAL;
> }
>
> @@ -280,9 +280,6 @@ 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 +297,20 @@ 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)
> + ret = process_data(&local_skb, dev, chan);
> + if (ret < 0) {
> + 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..d5bdeba 100644
> --- a/net/ieee802154/6lowpan_rtnl.c
> +++ b/net/ieee802154/6lowpan_rtnl.c
> @@ -167,11 +167,13 @@ static int lowpan_give_skb_to_devices(struct sk_buff *skb,
> return stat;
> }
>
> -static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
> +static int process_data(struct sk_buff **skb_inout,
> + const struct ieee802154_hdr *hdr)
> {
> u8 iphc0, iphc1;
> struct ieee802154_addr_sa sa, da;
> void *sap, *dap;
> + struct sk_buff *skb = *skb_inout;
>
> raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
> /* at least two bytes will be used for the encoding */
> @@ -197,13 +199,11 @@ static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
> else
> dap = &da.hwaddr;
>
> - return lowpan_process_data(skb, skb->dev, sap, sa.addr_type,
> + return lowpan_process_data(skb_inout, skb->dev, sap, sa.addr_type,
> IEEE802154_ADDR_LEN, dap, da.addr_type,
> - IEEE802154_ADDR_LEN, iphc0, iphc1,
> - lowpan_give_skb_to_devices);
> + IEEE802154_ADDR_LEN, iphc0, iphc1);
>
> drop:
> - kfree_skb(skb);
> return -EINVAL;
> }
>
> @@ -478,36 +478,35 @@ 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;
> + ret = NET_RX_SUCCESS;
> } else {
> switch (skb->data[0] & 0xe0) {
> case LOWPAN_DISPATCH_IPHC: /* ipv6 datagram */
> - ret = process_data(skb, &hdr);
> - if (ret == NET_RX_DROP)
> + ret = process_data(&skb, &hdr);
> + if (ret < 0)
> goto drop;
> break;
> case LOWPAN_DISPATCH_FRAG1: /* first fragment header */
> ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
can also return "-1" for error but in this case the skb is already freed.
so some else if with NET_RX_DROP. I know it was not handled before but we
should handle this right now, when we care about the error handling.
> if (ret == 1) {
> - ret = process_data(skb, &hdr);
> - if (ret == NET_RX_DROP)
> + ret = process_data(&skb, &hdr);
> + if (ret < 0)
> goto drop;
this function returning an errno, you can't return the errno here. goto
drop returns the ret variable. Maybe just make a return NET_RX_DROP at
drop. We should never return a different variable.
Also this need to be drop_skb at several places in this code, we don't
have a kfree_skb at process_data anymore. This leaks memory.
> + } else {
> + return NET_RX_SUCCESS;
> }
> break;
> case LOWPAN_DISPATCH_FRAGN: /* next fragments headers */
> ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
same here.
> if (ret == 1) {
> - ret = process_data(skb, &hdr);
> - if (ret == NET_RX_DROP)
> + ret = process_data(&skb, &hdr);
> + if (ret < 0)
> goto drop;
same here.
> + } else {
> + return NET_RX_SUCCESS;
> }
> break;
> default:
> @@ -515,7 +514,16 @@ 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;
> + ret = lowpan_give_skb_to_devices(skb, NULL);
grml, see possible merge conflicts here. In next should be no dev
parameter anymore. Nevertheless should easy to fix it.
> + if (ret < 0)
> + goto drop_skb;
> +
Also here that's too broken here. In lowpan_give_skb_to_devices we have
mixed errno and NET_RX_SUCCESS for the return variable, we need to
clean this up. Maybe just return the NET_RX_SUCCESS|NET_RX_DROP return
value from netif_rx call.
> + kfree_skb(skb);
consume_skb here.
Simple on error kfree_skb, not a error consume_skb or dev_kfree_skb. I
prefer consume_skb.
- Alex
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