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    Subject[PATCH 2/6] ipv6: Remove all uses of LL_ALLOCATED_SPACE
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    ipv6: Remove all uses of LL_ALLOCATED_SPACE

    The macro LL_ALLOCATED_SPACE was ill-conceived. It applies the
    alignment to the sum of needed_headroom and needed_tailroom. As
    the amount that is then reserved for head room is needed_headroom
    with alignment, this means that the tail room left may be too small.

    This patch replaces all uses of LL_ALLOCATED_SPACE in net/ipv6
    with the macro LL_RESERVED_SPACE and direct reference to
    needed_tailroom.

    This also fixes the problem with needed_headroom changing between
    allocating the skb and reserving the head room.

    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
    ---

    net/ipv6/ip6_output.c | 8 ++++++--
    net/ipv6/mcast.c | 12 ++++++++----
    net/ipv6/ndisc.c | 13 +++++++++----
    net/ipv6/raw.c | 6 ++++--
    4 files changed, 27 insertions(+), 12 deletions(-)

    diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
    index 84d0bd5..68ef97f 100644
    --- a/net/ipv6/ip6_output.c
    +++ b/net/ipv6/ip6_output.c
    @@ -631,6 +631,7 @@ int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
    struct ipv6hdr *tmp_hdr;
    struct frag_hdr *fh;
    unsigned int mtu, hlen, left, len;
    + int hroom, troom;
    __be32 frag_id = 0;
    int ptr, offset = 0, err=0;
    u8 *prevhdr, nexthdr = 0;
    @@ -797,6 +798,8 @@ slow_path:
    */

    *prevhdr = NEXTHDR_FRAGMENT;
    + hroom = LL_RESERVED_SPACE(rt->dst.dev);
    + troom = rt->dst.dev->needed_tailroom;

    /*
    * Keep copying data until we run out.
    @@ -815,7 +818,8 @@ slow_path:
    * Allocate buffer.
    */

    - if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_ALLOCATED_SPACE(rt->dst.dev), GFP_ATOMIC)) == NULL) {
    + if ((frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
    + hroom + troom, GFP_ATOMIC)) == NULL) {
    NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
    IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
    IPSTATS_MIB_FRAGFAILS);
    @@ -828,7 +832,7 @@ slow_path:
    */

    ip6_copy_metadata(frag, skb);
    - skb_reserve(frag, LL_RESERVED_SPACE(rt->dst.dev));
    + skb_reserve(frag, hroom);
    skb_put(frag, len + hlen + sizeof(struct frag_hdr));
    skb_reset_network_header(frag);
    fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
    diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
    index ee7839f..7b94beb 100644
    --- a/net/ipv6/mcast.c
    +++ b/net/ipv6/mcast.c
    @@ -1343,13 +1343,15 @@ static struct sk_buff *mld_newpack(struct net_device *dev, int size)
    struct mld2_report *pmr;
    struct in6_addr addr_buf;
    const struct in6_addr *saddr;
    + int hlen = LL_RESERVED_SPACE(dev);
    + int tlen = dev->needed_tailroom;
    int err;
    u8 ra[8] = { IPPROTO_ICMPV6, 0,
    IPV6_TLV_ROUTERALERT, 2, 0, 0,
    IPV6_TLV_PADN, 0 };

    /* we assume size > sizeof(ra) here */
    - size += LL_ALLOCATED_SPACE(dev);
    + size += hlen + tlen;
    /* limit our allocations to order-0 page */
    size = min_t(int, size, SKB_MAX_ORDER(0, 0));
    skb = sock_alloc_send_skb(sk, size, 1, &err);
    @@ -1357,7 +1359,7 @@ static struct sk_buff *mld_newpack(struct net_device *dev, int size)
    if (!skb)
    return NULL;

    - skb_reserve(skb, LL_RESERVED_SPACE(dev));
    + skb_reserve(skb, hlen);

    if (ipv6_get_lladdr(dev, &addr_buf, IFA_F_TENTATIVE)) {
    /* <draft-ietf-magma-mld-source-05.txt>:
    @@ -1723,6 +1725,8 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
    struct mld_msg *hdr;
    const struct in6_addr *snd_addr, *saddr;
    struct in6_addr addr_buf;
    + int hlen = LL_RESERVED_SPACE(dev);
    + int tlen = dev->needed_tailroom;
    int err, len, payload_len, full_len;
    u8 ra[8] = { IPPROTO_ICMPV6, 0,
    IPV6_TLV_ROUTERALERT, 2, 0, 0,
    @@ -1744,7 +1748,7 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
    IPSTATS_MIB_OUT, full_len);
    rcu_read_unlock();

    - skb = sock_alloc_send_skb(sk, LL_ALLOCATED_SPACE(dev) + full_len, 1, &err);
    + skb = sock_alloc_send_skb(sk, hlen + tlen + full_len, 1, &err);

    if (skb == NULL) {
    rcu_read_lock();
    @@ -1754,7 +1758,7 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
    return;
    }

    - skb_reserve(skb, LL_RESERVED_SPACE(dev));
    + skb_reserve(skb, hlen);

    if (ipv6_get_lladdr(dev, &addr_buf, IFA_F_TENTATIVE)) {
    /* <draft-ietf-magma-mld-source-05.txt>:
    diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
    index 44e5b7f..5f191c4 100644
    --- a/net/ipv6/ndisc.c
    +++ b/net/ipv6/ndisc.c
    @@ -446,6 +446,8 @@ struct sk_buff *ndisc_build_skb(struct net_device *dev,
    struct sock *sk = net->ipv6.ndisc_sk;
    struct sk_buff *skb;
    struct icmp6hdr *hdr;
    + int hlen = LL_RESERVED_SPACE(dev);
    + int tlen = dev->needed_tailroom;
    int len;
    int err;
    u8 *opt;
    @@ -459,7 +461,7 @@ struct sk_buff *ndisc_build_skb(struct net_device *dev,

    skb = sock_alloc_send_skb(sk,
    (MAX_HEADER + sizeof(struct ipv6hdr) +
    - len + LL_ALLOCATED_SPACE(dev)),
    + len + hlen + tlen),
    1, &err);
    if (!skb) {
    ND_PRINTK0(KERN_ERR
    @@ -468,7 +470,7 @@ struct sk_buff *ndisc_build_skb(struct net_device *dev,
    return NULL;
    }

    - skb_reserve(skb, LL_RESERVED_SPACE(dev));
    + skb_reserve(skb, hlen);
    ip6_nd_hdr(sk, skb, dev, saddr, daddr, IPPROTO_ICMPV6, len);

    skb->transport_header = skb->tail;
    @@ -1533,6 +1535,7 @@ void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
    struct inet6_dev *idev;
    struct flowi6 fl6;
    u8 *opt;
    + int hlen, tlen;
    int rd_len;
    int err;
    u8 ha_buf[MAX_ADDR_LEN], *ha = NULL;
    @@ -1590,9 +1593,11 @@ void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
    rd_len &= ~0x7;
    len += rd_len;

    + hlen = LL_RESERVED_SPACE(dev);
    + tlen = dev->needed_tailroom;
    buff = sock_alloc_send_skb(sk,
    (MAX_HEADER + sizeof(struct ipv6hdr) +
    - len + LL_ALLOCATED_SPACE(dev)),
    + len + hlen + tlen),
    1, &err);
    if (buff == NULL) {
    ND_PRINTK0(KERN_ERR
    @@ -1601,7 +1606,7 @@ void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
    goto release;
    }

    - skb_reserve(buff, LL_RESERVED_SPACE(dev));
    + skb_reserve(buff, hlen);
    ip6_nd_hdr(sk, buff, dev, &saddr_buf, &ipv6_hdr(skb)->saddr,
    IPPROTO_ICMPV6, len);

    diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
    index 331af3b..638fb2a 100644
    --- a/net/ipv6/raw.c
    +++ b/net/ipv6/raw.c
    @@ -610,6 +610,8 @@ static int rawv6_send_hdrinc(struct sock *sk, void *from, int length,
    struct sk_buff *skb;
    int err;
    struct rt6_info *rt = (struct rt6_info *)*dstp;
    + int hlen = LL_RESERVED_SPACE(rt->dst.dev);
    + int tlen = rt->dst.dev->needed_tailroom;

    if (length > rt->dst.dev->mtu) {
    ipv6_local_error(sk, EMSGSIZE, fl6, rt->dst.dev->mtu);
    @@ -619,11 +621,11 @@ static int rawv6_send_hdrinc(struct sock *sk, void *from, int length,
    goto out;

    skb = sock_alloc_send_skb(sk,
    - length + LL_ALLOCATED_SPACE(rt->dst.dev) + 15,
    + length + hlen + tlen + 15,
    flags & MSG_DONTWAIT, &err);
    if (skb == NULL)
    goto error;
    - skb_reserve(skb, LL_RESERVED_SPACE(rt->dst.dev));
    + skb_reserve(skb, hlen);

    skb->priority = sk->sk_priority;
    skb->mark = sk->sk_mark;

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      Last update: 2011-11-18 13:23    [W:0.030 / U:58.800 seconds]
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