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seg6: export get_srh() for ICMP handling

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An ICMP error message can contain in its message body part of an IPv6
packet which invoked the error. Such a packet might contain a segment
router header. Export get_srh() so the ICMP code can make use of it.

Since his changes the scope of the function from local to global, add
the seg6_ prefix to keep the namespace clean. And move it into seg6.c
so it is always available, not just when IPV6_SEG6_LWTUNNEL is
enabled.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andrew Lunn 2022-01-03 18:11:30 +01:00 committed by David S. Miller
parent e8fe9e8308
commit fa55a7d745
3 changed files with 32 additions and 31 deletions
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1
include/net/seg6.h
View File

@ -58,6 +58,7 @@ extern int seg6_local_init(void);
extern void seg6_local_exit(void);
extern bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len, bool reduced);
extern struct ipv6_sr_hdr *seg6_get_srh(struct sk_buff *skb, int flags);
extern int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh,
int proto);
extern int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh);

29
net/ipv6/seg6.c
View File

@ -75,6 +75,35 @@ bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len, bool reduced)
return true;
}
struct ipv6_sr_hdr *seg6_get_srh(struct sk_buff *skb, int flags)
{
struct ipv6_sr_hdr *srh;
int len, srhoff = 0;
if (ipv6_find_hdr(skb, &srhoff, IPPROTO_ROUTING, NULL, &flags) < 0)
return NULL;
if (!pskb_may_pull(skb, srhoff + sizeof(*srh)))
return NULL;
srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
len = (srh->hdrlen + 1) << 3;
if (!pskb_may_pull(skb, srhoff + len))
return NULL;
/* note that pskb_may_pull may change pointers in header;
* for this reason it is necessary to reload them when needed.
*/
srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
if (!seg6_validate_srh(srh, len, true))
return NULL;
return srh;
}
static struct genl_family seg6_genl_family;
static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {

33
net/ipv6/seg6_local.c
View File

@ -150,40 +150,11 @@ static struct seg6_local_lwt *seg6_local_lwtunnel(struct lwtunnel_state *lwt)
return (struct seg6_local_lwt *)lwt->data;
}
static struct ipv6_sr_hdr *get_srh(struct sk_buff *skb, int flags)
{
struct ipv6_sr_hdr *srh;
int len, srhoff = 0;
if (ipv6_find_hdr(skb, &srhoff, IPPROTO_ROUTING, NULL, &flags) < 0)
return NULL;
if (!pskb_may_pull(skb, srhoff + sizeof(*srh)))
return NULL;
srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
len = (srh->hdrlen + 1) << 3;
if (!pskb_may_pull(skb, srhoff + len))
return NULL;
/* note that pskb_may_pull may change pointers in header;
* for this reason it is necessary to reload them when needed.
*/
srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
if (!seg6_validate_srh(srh, len, true))
return NULL;
return srh;
}
static struct ipv6_sr_hdr *get_and_validate_srh(struct sk_buff *skb)
{
struct ipv6_sr_hdr *srh;
srh = get_srh(skb, IP6_FH_F_SKIP_RH);
srh = seg6_get_srh(skb, IP6_FH_F_SKIP_RH);
if (!srh)
return NULL;
@ -200,7 +171,7 @@ static bool decap_and_validate(struct sk_buff *skb, int proto)
struct ipv6_sr_hdr *srh;
unsigned int off = 0;
srh = get_srh(skb, 0);
srh = seg6_get_srh(skb, 0);
if (srh && srh->segments_left > 0)
return false;