[PATCH 3.2 008/152] ipv4: Remove all uses of LL_ALLOCATED_SPACE

Ben Hutchings
2015-02-17T01:46:53Z

From: Herbert Xu <herbert@gondor.apana.org.au>

commit 660882432909dbe611f1792eda158188065cb9f1 upstream.

ipv4: 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/ipv4
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/ipv4/arp.c | 6 ++++--
net/ipv4/igmp.c | 13 +++++++++----
net/ipv4/ipconfig.c | 6 ++++--
net/ipv4/raw.c | 7 +++++--
4 files changed, 22 insertions(+), 10 deletions(-)

--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -592,16 +592,18 @@ struct sk_buff *arp_create(int type, int
struct sk_buff *skb;
struct arphdr *arp;
unsigned char *arp_ptr;
+ int hlen = LL_RESERVED_SPACE(dev);
+ int tlen = dev->needed_tailroom;

/*
* Allocate a buffer
*/

- skb = alloc_skb(arp_hdr_len(dev) + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
+ skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
if (skb == NULL)
return NULL;

- skb_reserve(skb, LL_RESERVED_SPACE(dev));
+ skb_reserve(skb, hlen);
skb_reset_network_header(skb);
arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
skb->dev = dev;
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -304,9 +304,11 @@ static struct sk_buff *igmpv3_newpack(st
struct igmpv3_report *pig;
struct net *net = dev_net(dev);
struct flowi4 fl4;
+ int hlen = LL_RESERVED_SPACE(dev);
+ int tlen = dev->needed_tailroom;

while (1) {
- skb = alloc_skb(size + LL_ALLOCATED_SPACE(dev),
+ skb = alloc_skb(size + hlen + tlen,
GFP_ATOMIC | __GFP_NOWARN);
if (skb)
break;
@@ -327,7 +329,7 @@ static struct sk_buff *igmpv3_newpack(st
skb_dst_set(skb, &rt->dst);
skb->dev = dev;

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

skb_reset_network_header(skb);
pip = ip_hdr(skb);
@@ -647,6 +649,7 @@ static int igmp_send_report(struct in_de
__be32 group = pmc ? pmc->multiaddr : 0;
struct flowi4 fl4;
__be32 dst;
+ int hlen, tlen;

if (type == IGMPV3_HOST_MEMBERSHIP_REPORT)
return igmpv3_send_report(in_dev, pmc);
@@ -661,7 +664,9 @@ static int igmp_send_report(struct in_de
if (IS_ERR(rt))
return -1;

- skb = alloc_skb(IGMP_SIZE+LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
+ hlen = LL_RESERVED_SPACE(dev);
+ tlen = dev->needed_tailroom;
+ skb = alloc_skb(IGMP_SIZE + hlen + tlen, GFP_ATOMIC);
if (skb == NULL) {
ip_rt_put(rt);
return -1;
@@ -669,7 +674,7 @@ static int igmp_send_report(struct in_de

skb_dst_set(skb, &rt->dst);

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

skb_reset_network_header(skb);
iph = ip_hdr(skb);
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -767,13 +767,15 @@ static void __init ic_bootp_send_if(stru
struct sk_buff *skb;
struct bootp_pkt *b;
struct iphdr *h;
+ int hlen = LL_RESERVED_SPACE(dev);
+ int tlen = dev->needed_tailroom;

/* Allocate packet */
- skb = alloc_skb(sizeof(struct bootp_pkt) + LL_ALLOCATED_SPACE(dev) + 15,
+ skb = alloc_skb(sizeof(struct bootp_pkt) + hlen + tlen + 15,
GFP_KERNEL);
if (!skb)
return;
- skb_reserve(skb, LL_RESERVED_SPACE(dev));
+ skb_reserve(skb, hlen);
b = (struct bootp_pkt *) skb_put(skb, sizeof(struct bootp_pkt));
memset(b, 0, sizeof(struct bootp_pkt));

--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -329,6 +329,7 @@ static int raw_send_hdrinc(struct sock *
unsigned int iphlen;
int err;
struct rtable *rt = *rtp;
+ int hlen, tlen;

if (length > rt->dst.dev->mtu) {
ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
@@ -338,12 +339,14 @@ static int raw_send_hdrinc(struct sock *
if (flags&MSG_PROBE)
goto out;

+ hlen = LL_RESERVED_SPACE(rt->dst.dev);
+ tlen = rt->dst.dev->needed_tailroom;
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;