net: add skb_checksum_setup
This patch adds a function to set up the partial checksum offset for IP packets (and optionally re-calculate the pseudo-header checksum) into the core network code. The implementation was previously private and duplicated between xen-netback and xen-netfront, however it is not xen-specific and is potentially useful to any network driver. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Veaceslav Falico <vfalico@redhat.com> Cc: Alexander Duyck <alexander.h.duyck@intel.com> Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paul Durrant
committed by
David S. Miller
David S. Miller
parent
b86f81cca9
commit
ed1f50c3a7
@@ -65,6 +65,7 @@
|
||||
#include <net/dst.h>
|
||||
#include <net/sock.h>
|
||||
#include <net/checksum.h>
|
||||
#include <net/ip6_checksum.h>
|
||||
#include <net/xfrm.h>
|
||||
|
||||
#include <asm/uaccess.h>
|
||||
@@ -3549,6 +3550,278 @@ bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(skb_partial_csum_set);
|
||||
|
||||
static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len,
|
||||
unsigned int max)
|
||||
{
|
||||
if (skb_headlen(skb) >= len)
|
||||
return 0;
|
||||
|
||||
/* If we need to pullup then pullup to the max, so we
|
||||
* won't need to do it again.
|
||||
*/
|
||||
if (max > skb->len)
|
||||
max = skb->len;
|
||||
|
||||
if (__pskb_pull_tail(skb, max - skb_headlen(skb)) == NULL)
|
||||
return -ENOMEM;
|
||||
|
||||
if (skb_headlen(skb) < len)
|
||||
return -EPROTO;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* 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)
|
||||
{
|
||||
unsigned int off;
|
||||
bool fragment;
|
||||
int err;
|
||||
|
||||
fragment = false;
|
||||
|
||||
err = skb_maybe_pull_tail(skb,
|
||||
sizeof(struct iphdr),
|
||||
MAX_IP_HDR_LEN);
|
||||
if (err < 0)
|
||||
goto out;
|
||||
|
||||
if (ip_hdr(skb)->frag_off & htons(IP_OFFSET | IP_MF))
|
||||
fragment = true;
|
||||
|
||||
off = ip_hdrlen(skb);
|
||||
|
||||
err = -EPROTO;
|
||||
|
||||
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;
|
||||
}
|
||||
|
||||
err = 0;
|
||||
|
||||
out:
|
||||
return err;
|
||||
}
|
||||
|
||||
/* This value should be large enough to cover a tagged ethernet header plus
|
||||
* an IPv6 header, all options, and a maximal TCP or UDP header.
|
||||
*/
|
||||
#define MAX_IPV6_HDR_LEN 256
|
||||
|
||||
#define OPT_HDR(type, skb, off) \
|
||||
(type *)(skb_network_header(skb) + (off))
|
||||
|
||||
static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate)
|
||||
{
|
||||
int err;
|
||||
u8 nexthdr;
|
||||
unsigned int off;
|
||||
unsigned int len;
|
||||
bool fragment;
|
||||
bool done;
|
||||
|
||||
fragment = false;
|
||||
done = false;
|
||||
|
||||
off = sizeof(struct ipv6hdr);
|
||||
|
||||
err = skb_maybe_pull_tail(skb, off, MAX_IPV6_HDR_LEN);
|
||||
if (err < 0)
|
||||
goto out;
|
||||
|
||||
nexthdr = ipv6_hdr(skb)->nexthdr;
|
||||
|
||||
len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len);
|
||||
while (off <= len && !done) {
|
||||
switch (nexthdr) {
|
||||
case IPPROTO_DSTOPTS:
|
||||
case IPPROTO_HOPOPTS:
|
||||
case IPPROTO_ROUTING: {
|
||||
struct ipv6_opt_hdr *hp;
|
||||
|
||||
err = skb_maybe_pull_tail(skb,
|
||||
off +
|
||||
sizeof(struct ipv6_opt_hdr),
|
||||
MAX_IPV6_HDR_LEN);
|
||||
if (err < 0)
|
||||
goto out;
|
||||
|
||||
hp = OPT_HDR(struct ipv6_opt_hdr, skb, off);
|
||||
nexthdr = hp->nexthdr;
|
||||
off += ipv6_optlen(hp);
|
||||
break;
|
||||
}
|
||||
case IPPROTO_AH: {
|
||||
struct ip_auth_hdr *hp;
|
||||
|
||||
err = skb_maybe_pull_tail(skb,
|
||||
off +
|
||||
sizeof(struct ip_auth_hdr),
|
||||
MAX_IPV6_HDR_LEN);
|
||||
if (err < 0)
|
||||
goto out;
|
||||
|
||||
hp = OPT_HDR(struct ip_auth_hdr, skb, off);
|
||||
nexthdr = hp->nexthdr;
|
||||
off += ipv6_authlen(hp);
|
||||
break;
|
||||
}
|
||||
case IPPROTO_FRAGMENT: {
|
||||
struct frag_hdr *hp;
|
||||
|
||||
err = skb_maybe_pull_tail(skb,
|
||||
off +
|
||||
sizeof(struct frag_hdr),
|
||||
MAX_IPV6_HDR_LEN);
|
||||
if (err < 0)
|
||||
goto out;
|
||||
|
||||
hp = OPT_HDR(struct frag_hdr, skb, off);
|
||||
|
||||
if (hp->frag_off & htons(IP6_OFFSET | IP6_MF))
|
||||
fragment = true;
|
||||
|
||||
nexthdr = hp->nexthdr;
|
||||
off += sizeof(struct frag_hdr);
|
||||
break;
|
||||
}
|
||||
default:
|
||||
done = true;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
err = -EPROTO;
|
||||
|
||||
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;
|
||||
}
|
||||
|
||||
err = 0;
|
||||
|
||||
out:
|
||||
return err;
|
||||
}
|
||||
|
||||
/**
|
||||
* skb_checksum_setup - set up partial checksum offset
|
||||
* @skb: the skb to set up
|
||||
* @recalculate: if true the pseudo-header checksum will be recalculated
|
||||
*/
|
||||
int skb_checksum_setup(struct sk_buff *skb, bool recalculate)
|
||||
{
|
||||
int err;
|
||||
|
||||
switch (skb->protocol) {
|
||||
case htons(ETH_P_IP):
|
||||
err = skb_checksum_setup_ip(skb, recalculate);
|
||||
break;
|
||||
|
||||
case htons(ETH_P_IPV6):
|
||||
err = skb_checksum_setup_ipv6(skb, recalculate);
|
||||
break;
|
||||
|
||||
default:
|
||||
err = -EPROTO;
|
||||
break;
|
||||
}
|
||||
|
||||
return err;
|
||||
}
|
||||
EXPORT_SYMBOL(skb_checksum_setup);
|
||||
|
||||
void __skb_warn_lro_forwarding(const struct sk_buff *skb)
|
||||
{
|
||||
net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
|
||||
|
||||
Reference in New Issue
Block a user