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Message-ID: <9AAE0902D5BC7E449B7C8E4E778ABCD028296C@AMSPEX01CL01.citrite.net>
Date: Wed, 12 Mar 2014 09:46:09 +0000
From: Paul Durrant <Paul.Durrant@...rix.com>
To: Jan Beulich <JBeulich@...e.com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC: "davem@...emloft.net" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>
Subject: RE: [PATCH v2 net-next] consolidate duplicate code is
skb_checksum_setup() helpers
> -----Original Message-----
> From: Jan Beulich [mailto:JBeulich@...e.com]
> Sent: 11 March 2014 13:56
> To: netdev@...r.kernel.org
> Cc: Paul Durrant; davem@...emloft.net; Eric Dumazet
> Subject: [PATCH v2 net-next] consolidate duplicate code is
> skb_checksum_setup() helpers
>
> consolidate duplicate code is skb_checksum_setup() helpers
>
> Realizing that the skb_maybe_pull_tail() calls in the IP-protocol
> specific portions of both helpers are terminal ones (i.e. no further
> pulls are expected), their maximum size to be pulled can be made match
> their minimal size needed, thus making the code identical and hence
> possible to be moved into another helper.
>
> Signed-off-by: Jan Beulich <jbeulich@...e.com>
> Cc: Paul Durrant <paul.durrant@...rix.com>
> Cc: David Miller <davem@...emloft.net>
> Cc: Eric Dumazet <edumazet@...gle.com>
> ---
> v2: Use MAX_TCP_HDR_LEN. Use __sum16 instead of __be16.
Looks ok to me.
Reviewed-by: Paul Durrant <paul.durrant@...rix.com>
> ---
> net/core/skbuff.c | 144 +++++++++++++++++++---------------------------------
> --
> 1 file changed, 52 insertions(+), 92 deletions(-)
>
> --- 3.14-rc6/net/core/skbuff.c
> +++ 3.14-rc6-skb-checksum-setup-ip/net/core/skbuff.c
> @@ -3540,15 +3540,47 @@ static int skb_maybe_pull_tail(struct sk
> return 0;
> }
>
> +#define MAX_TCP_HDR_LEN (15 * 4)
> +
> +static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb,
> + typeof(IPPROTO_IP) proto,
> + unsigned int off)
> +{
> + switch (proto) {
> + int err;
> +
> + case IPPROTO_TCP:
> + err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr),
> + off + MAX_TCP_HDR_LEN);
> + if (!err && !skb_partial_csum_set(skb, off,
> + offsetof(struct tcphdr,
> + check)))
> + err = -EPROTO;
> + return err ? ERR_PTR(err) : &tcp_hdr(skb)->check;
> +
> + case IPPROTO_UDP:
> + err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr),
> + off + sizeof(struct udphdr));
> + if (!err && !skb_partial_csum_set(skb, off,
> + offsetof(struct udphdr,
> + check)))
> + err = -EPROTO;
> + return err ? ERR_PTR(err) : &udp_hdr(skb)->check;
> + }
> +
> + return ERR_PTR(-EPROTO);
> +}
> +
> /* This value should be large enough to cover a tagged ethernet header plus
> * maximally sized IP and TCP or UDP headers.
> */
> #define MAX_IP_HDR_LEN 128
>
> -static int skb_checksum_setup_ip(struct sk_buff *skb, bool recalculate)
> +static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate)
> {
> unsigned int off;
> bool fragment;
> + __sum16 *csum;
> int err;
>
> fragment = false;
> @@ -3569,51 +3601,15 @@ static int skb_checksum_setup_ip(struct
> if (fragment)
> goto out;
>
> - switch (ip_hdr(skb)->protocol) {
> - case IPPROTO_TCP:
> - err = skb_maybe_pull_tail(skb,
> - off + sizeof(struct tcphdr),
> - MAX_IP_HDR_LEN);
> - if (err < 0)
> - goto out;
> -
> - if (!skb_partial_csum_set(skb, off,
> - offsetof(struct tcphdr, check))) {
> - err = -EPROTO;
> - goto out;
> - }
> -
> - if (recalculate)
> - tcp_hdr(skb)->check =
> - ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
> - ip_hdr(skb)->daddr,
> - skb->len - off,
> - IPPROTO_TCP, 0);
> - break;
> - case IPPROTO_UDP:
> - err = skb_maybe_pull_tail(skb,
> - off + sizeof(struct udphdr),
> - MAX_IP_HDR_LEN);
> - if (err < 0)
> - goto out;
> -
> - if (!skb_partial_csum_set(skb, off,
> - offsetof(struct udphdr, check))) {
> - err = -EPROTO;
> - goto out;
> - }
> -
> - if (recalculate)
> - udp_hdr(skb)->check =
> - ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
> - ip_hdr(skb)->daddr,
> - skb->len - off,
> - IPPROTO_UDP, 0);
> - break;
> - default:
> - goto out;
> - }
> -
> + csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off);
> + if (IS_ERR(csum))
> + return PTR_ERR(csum);
> +
> + if (recalculate)
> + *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
> + ip_hdr(skb)->daddr,
> + skb->len - off,
> + ip_hdr(skb)->protocol, 0);
> err = 0;
>
> out:
> @@ -3636,6 +3632,7 @@ static int skb_checksum_setup_ipv6(struc
> unsigned int len;
> bool fragment;
> bool done;
> + __sum16 *csum;
>
> fragment = false;
> done = false;
> @@ -3713,51 +3710,14 @@ static int skb_checksum_setup_ipv6(struc
> if (!done || fragment)
> goto out;
>
> - switch (nexthdr) {
> - case IPPROTO_TCP:
> - err = skb_maybe_pull_tail(skb,
> - off + sizeof(struct tcphdr),
> - MAX_IPV6_HDR_LEN);
> - if (err < 0)
> - goto out;
> -
> - if (!skb_partial_csum_set(skb, off,
> - offsetof(struct tcphdr, check))) {
> - err = -EPROTO;
> - goto out;
> - }
> -
> - if (recalculate)
> - tcp_hdr(skb)->check =
> - ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
> - &ipv6_hdr(skb)->daddr,
> - skb->len - off,
> - IPPROTO_TCP, 0);
> - break;
> - case IPPROTO_UDP:
> - err = skb_maybe_pull_tail(skb,
> - off + sizeof(struct udphdr),
> - MAX_IPV6_HDR_LEN);
> - if (err < 0)
> - goto out;
> -
> - if (!skb_partial_csum_set(skb, off,
> - offsetof(struct udphdr, check))) {
> - err = -EPROTO;
> - goto out;
> - }
> -
> - if (recalculate)
> - udp_hdr(skb)->check =
> - ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
> - &ipv6_hdr(skb)->daddr,
> - skb->len - off,
> - IPPROTO_UDP, 0);
> - break;
> - default:
> - goto out;
> - }
> -
> + csum = skb_checksum_setup_ip(skb, nexthdr, off);
> + if (IS_ERR(csum))
> + return PTR_ERR(csum);
> +
> + if (recalculate)
> + *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
> + &ipv6_hdr(skb)->daddr,
> + skb->len - off, nexthdr, 0);
> err = 0;
>
> out:
> @@ -3775,7 +3735,7 @@ int skb_checksum_setup(struct sk_buff *s
>
> switch (skb->protocol) {
> case htons(ETH_P_IP):
> - err = skb_checksum_setup_ip(skb, recalculate);
> + err = skb_checksum_setup_ipv4(skb, recalculate);
> break;
>
> case htons(ETH_P_IPV6):
>
--
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