From 2ca7b0ac022aa0158599178fe1056b1ba9ec8b97 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 14 Oct 2007 00:39:55 -0700 Subject: [PATCH] [NETFILTER]: Avoid skb_copy/pskb_copy/skb_realloc_headroom This patch replaces unnecessary uses of skb_copy, pskb_copy and skb_realloc_headroom by functions such as skb_make_writable and pskb_expand_head. This allows us to remove the double pointers later. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/bridge/netfilter/ebt_dnat.c | 13 +++--------- net/bridge/netfilter/ebt_redirect.c | 13 +++--------- net/bridge/netfilter/ebt_snat.c | 13 +++--------- net/ipv4/netfilter.c | 31 +++++++++-------------------- net/ipv4/netfilter/arpt_mangle.c | 14 +++---------- net/ipv4/netfilter/ip_queue.c | 22 ++++++++------------ net/ipv4/netfilter/nf_nat_helper.c | 10 +--------- net/ipv6/netfilter/ip6_queue.c | 18 ++++++----------- net/netfilter/nfnetlink_queue.c | 18 ++++++----------- net/netfilter/xt_TCPMSS.c | 10 +++------- 10 files changed, 45 insertions(+), 117 deletions(-) diff --git a/net/bridge/netfilter/ebt_dnat.c b/net/bridge/netfilter/ebt_dnat.c index 4582659dff..9d74dee20a 100644 --- a/net/bridge/netfilter/ebt_dnat.c +++ b/net/bridge/netfilter/ebt_dnat.c @@ -8,6 +8,7 @@ * */ +#include #include #include #include @@ -19,17 +20,9 @@ static int ebt_target_dnat(struct sk_buff **pskb, unsigned int hooknr, { struct ebt_nat_info *info = (struct ebt_nat_info *)data; - if (skb_shared(*pskb) || skb_cloned(*pskb)) { - struct sk_buff *nskb; + if (skb_make_writable(*pskb, 0)) + return NF_DROP; - nskb = skb_copy(*pskb, GFP_ATOMIC); - if (!nskb) - return NF_DROP; - if ((*pskb)->sk) - skb_set_owner_w(nskb, (*pskb)->sk); - kfree_skb(*pskb); - *pskb = nskb; - } memcpy(eth_hdr(*pskb)->h_dest, info->mac, ETH_ALEN); return info->target; } diff --git a/net/bridge/netfilter/ebt_redirect.c b/net/bridge/netfilter/ebt_redirect.c index 9f378eab72..81371cd01b 100644 --- a/net/bridge/netfilter/ebt_redirect.c +++ b/net/bridge/netfilter/ebt_redirect.c @@ -8,6 +8,7 @@ * */ +#include #include #include #include @@ -20,17 +21,9 @@ static int ebt_target_redirect(struct sk_buff **pskb, unsigned int hooknr, { struct ebt_redirect_info *info = (struct ebt_redirect_info *)data; - if (skb_shared(*pskb) || skb_cloned(*pskb)) { - struct sk_buff *nskb; + if (skb_make_writable(*pskb, 0)) + return NF_DROP; - nskb = skb_copy(*pskb, GFP_ATOMIC); - if (!nskb) - return NF_DROP; - if ((*pskb)->sk) - skb_set_owner_w(nskb, (*pskb)->sk); - kfree_skb(*pskb); - *pskb = nskb; - } if (hooknr != NF_BR_BROUTING) memcpy(eth_hdr(*pskb)->h_dest, in->br_port->br->dev->dev_addr, ETH_ALEN); diff --git a/net/bridge/netfilter/ebt_snat.c b/net/bridge/netfilter/ebt_snat.c index a50722182b..b0c63684e2 100644 --- a/net/bridge/netfilter/ebt_snat.c +++ b/net/bridge/netfilter/ebt_snat.c @@ -8,6 +8,7 @@ * */ +#include #include #include #include @@ -21,17 +22,9 @@ static int ebt_target_snat(struct sk_buff **pskb, unsigned int hooknr, { struct ebt_nat_info *info = (struct ebt_nat_info *) data; - if (skb_shared(*pskb) || skb_cloned(*pskb)) { - struct sk_buff *nskb; + if (skb_make_writable(*pskb, 0)) + return NF_DROP; - nskb = skb_copy(*pskb, GFP_ATOMIC); - if (!nskb) - return NF_DROP; - if ((*pskb)->sk) - skb_set_owner_w(nskb, (*pskb)->sk); - kfree_skb(*pskb); - *pskb = nskb; - } memcpy(eth_hdr(*pskb)->h_source, info->mac, ETH_ALEN); if (!(info->target & NAT_ARP_BIT) && eth_hdr(*pskb)->h_proto == htons(ETH_P_ARP)) { diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c index b44192924f..d1e3012d89 100644 --- a/net/ipv4/netfilter.c +++ b/net/ipv4/netfilter.c @@ -3,6 +3,7 @@ #include #include #include +#include #include #include #include @@ -66,17 +67,10 @@ int ip_route_me_harder(struct sk_buff **pskb, unsigned addr_type) /* Change in oif may mean change in hh_len. */ hh_len = (*pskb)->dst->dev->hard_header_len; - if (skb_headroom(*pskb) < hh_len) { - struct sk_buff *nskb; - - nskb = skb_realloc_headroom(*pskb, hh_len); - if (!nskb) - return -1; - if ((*pskb)->sk) - skb_set_owner_w(nskb, (*pskb)->sk); - kfree_skb(*pskb); - *pskb = nskb; - } + if (skb_headroom(*pskb) < hh_len && + pskb_expand_head(*pskb, hh_len - skb_headroom(*pskb), 0, + GFP_ATOMIC)) + return -1; return 0; } @@ -107,17 +101,10 @@ int ip_xfrm_me_harder(struct sk_buff **pskb) /* Change in oif may mean change in hh_len. */ hh_len = (*pskb)->dst->dev->hard_header_len; - if (skb_headroom(*pskb) < hh_len) { - struct sk_buff *nskb; - - nskb = skb_realloc_headroom(*pskb, hh_len); - if (!nskb) - return -1; - if ((*pskb)->sk) - skb_set_owner_w(nskb, (*pskb)->sk); - kfree_skb(*pskb); - *pskb = nskb; - } + if (skb_headroom(*pskb) < hh_len && + pskb_expand_head(*pskb, hh_len - skb_headroom(*pskb), 0, + GFP_ATOMIC)) + return -1; return 0; } EXPORT_SYMBOL(ip_xfrm_me_harder); diff --git a/net/ipv4/netfilter/arpt_mangle.c b/net/ipv4/netfilter/arpt_mangle.c index c4bdab4759..0181f919a7 100644 --- a/net/ipv4/netfilter/arpt_mangle.c +++ b/net/ipv4/netfilter/arpt_mangle.c @@ -1,5 +1,6 @@ /* module that allows mangling of the arp payload */ #include +#include #include #include @@ -18,17 +19,8 @@ target(struct sk_buff **pskb, unsigned char *arpptr; int pln, hln; - if (skb_shared(*pskb) || skb_cloned(*pskb)) { - struct sk_buff *nskb; - - nskb = skb_copy(*pskb, GFP_ATOMIC); - if (!nskb) - return NF_DROP; - if ((*pskb)->sk) - skb_set_owner_w(nskb, (*pskb)->sk); - kfree_skb(*pskb); - *pskb = nskb; - } + if (skb_make_writable(*pskb, (*pskb)->len)) + return NF_DROP; arp = arp_hdr(*pskb); arpptr = skb_network_header(*pskb) + sizeof(*arp); diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c index 62d8867ca7..10a2ce09fd 100644 --- a/net/ipv4/netfilter/ip_queue.c +++ b/net/ipv4/netfilter/ip_queue.c @@ -335,6 +335,7 @@ static int ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e) { int diff; + int err; struct iphdr *user_iph = (struct iphdr *)v->payload; if (v->data_len < sizeof(*user_iph)) @@ -347,21 +348,14 @@ ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e) if (v->data_len > 0xFFFF) return -EINVAL; if (diff > skb_tailroom(e->skb)) { - struct sk_buff *newskb; - - newskb = skb_copy_expand(e->skb, - skb_headroom(e->skb), - diff, - GFP_ATOMIC); - if (newskb == NULL) { - printk(KERN_WARNING "ip_queue: OOM " - "in mangle, dropping packet\n"); - return -ENOMEM; + err = pskb_expand_head(e->skb, 0, + diff - skb_tailroom(e->skb), + GFP_ATOMIC); + if (err) { + printk(KERN_WARNING "ip_queue: error " + "in mangle, dropping packet: %d\n", -err); + return err; } - if (e->skb->sk) - skb_set_owner_w(newskb, e->skb->sk); - kfree_skb(e->skb); - e->skb = newskb; } skb_put(e->skb, diff); } diff --git a/net/ipv4/netfilter/nf_nat_helper.c b/net/ipv4/netfilter/nf_nat_helper.c index 6e81f7612b..40b429e454 100644 --- a/net/ipv4/netfilter/nf_nat_helper.c +++ b/net/ipv4/netfilter/nf_nat_helper.c @@ -113,20 +113,12 @@ static void mangle_contents(struct sk_buff *skb, /* Unusual, but possible case. */ static int enlarge_skb(struct sk_buff **pskb, unsigned int extra) { - struct sk_buff *nskb; - if ((*pskb)->len + extra > 65535) return 0; - nskb = skb_copy_expand(*pskb, skb_headroom(*pskb), extra, GFP_ATOMIC); - if (!nskb) + if (pskb_expand_head(*pskb, 0, extra - skb_tailroom(*pskb), GFP_ATOMIC)) return 0; - /* Transfer socket to new skb. */ - if ((*pskb)->sk) - skb_set_owner_w(nskb, (*pskb)->sk); - kfree_skb(*pskb); - *pskb = nskb; return 1; } diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c index d7080dd475..6413a30d9f 100644 --- a/net/ipv6/netfilter/ip6_queue.c +++ b/net/ipv6/netfilter/ip6_queue.c @@ -332,6 +332,7 @@ static int ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e) { int diff; + int err; struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload; if (v->data_len < sizeof(*user_iph)) @@ -344,21 +345,14 @@ ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e) if (v->data_len > 0xFFFF) return -EINVAL; if (diff > skb_tailroom(e->skb)) { - struct sk_buff *newskb; - - newskb = skb_copy_expand(e->skb, - skb_headroom(e->skb), - diff, - GFP_ATOMIC); - if (newskb == NULL) { + err = pskb_expand_head(e->skb, 0, + diff - skb_tailroom(e->skb), + GFP_ATOMIC); + if (err) { printk(KERN_WARNING "ip6_queue: OOM " "in mangle, dropping packet\n"); - return -ENOMEM; + return err; } - if (e->skb->sk) - skb_set_owner_w(newskb, e->skb->sk); - kfree_skb(e->skb); - e->skb = newskb; } skb_put(e->skb, diff); } diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index 6ba98acdd7..3ceeffcf6f 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -617,6 +617,7 @@ static int nfqnl_mangle(void *data, int data_len, struct nfqnl_queue_entry *e) { int diff; + int err; diff = data_len - e->skb->len; if (diff < 0) { @@ -626,21 +627,14 @@ nfqnl_mangle(void *data, int data_len, struct nfqnl_queue_entry *e) if (data_len > 0xFFFF) return -EINVAL; if (diff > skb_tailroom(e->skb)) { - struct sk_buff *newskb; - - newskb = skb_copy_expand(e->skb, - skb_headroom(e->skb), - diff, - GFP_ATOMIC); - if (newskb == NULL) { + err = pskb_expand_head(e->skb, 0, + diff - skb_tailroom(e->skb), + GFP_ATOMIC); + if (err) { printk(KERN_WARNING "nf_queue: OOM " "in mangle, dropping packet\n"); - return -ENOMEM; + return err; } - if (e->skb->sk) - skb_set_owner_w(newskb, e->skb->sk); - kfree_skb(e->skb); - e->skb = newskb; } skb_put(e->skb, diff); } diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c index 31b6f9d098..f111edf5f7 100644 --- a/net/netfilter/xt_TCPMSS.c +++ b/net/netfilter/xt_TCPMSS.c @@ -105,14 +105,10 @@ tcpmss_mangle_packet(struct sk_buff **pskb, * MSS Option not found ?! add it.. */ if (skb_tailroom((*pskb)) < TCPOLEN_MSS) { - struct sk_buff *newskb; - - newskb = skb_copy_expand(*pskb, skb_headroom(*pskb), - TCPOLEN_MSS, GFP_ATOMIC); - if (!newskb) + if (pskb_expand_head(*pskb, 0, + TCPOLEN_MSS - skb_tailroom(*pskb), + GFP_ATOMIC)) return -1; - kfree_skb(*pskb); - *pskb = newskb; tcph = (struct tcphdr *)(skb_network_header(*pskb) + tcphoff); } -- 2.39.5