Currently, if the socket is owned by the user, we drop the ICMP message. As a result SCTP forgets that path MTU changed and never adjusting it's estimate. This causes all subsequent packets to be fragmented. With this patch, we'll flag the association that it needs to udpate it's estimate based on the already updated routing information. Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com> Acked-by: Sridhar Samudrala <sri@us.ibm.com>
Introduce new function sctp_transport_update_pmtu that updates the transports and destination caches view of the path mtu. Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com> Acked-by: Sridhar Samudrala <sri@us.ibm.com>
When a transmitted packet is looped back directly, CHECKSUM_PARTIAL maps to the semantics of CHECKSUM_UNNECESSARY. Therefore we should treat it as such in the stack. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes
on 64bit architectures, allowing us to combine the 4 bytes hole left by the
layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4
64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN...
:-)
Many calculations that previously required that skb->{transport,network,
mac}_header be first converted to a pointer now can be done directly, being
meaningful as offsets or pointers.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With this we save 8 bytes per network packet, leaving a 4 bytes hole to be used
in further shrinking work, likely with the offsetization of other pointers,
such as ->{data,tail,end}, at the cost of adds, that were minimized by the
usual practice of setting skb->{mac,nh,n}.raw to a local variable that is then
accessed multiple times in each function, it also is not more expensive than
before with regards to most of the handling of such headers, like setting one
of these headers to another (transport to network, etc), or subtracting, adding
to/from it, comparing them, etc.
Now we have this layout for sk_buff on a x86_64 machine:
[acme@mica net-2.6.22]$ pahole vmlinux sk_buff
struct sk_buff {
struct sk_buff * next; /* 0 8 */
struct sk_buff * prev; /* 8 8 */
struct rb_node rb; /* 16 24 */
struct sock * sk; /* 40 8 */
ktime_t tstamp; /* 48 8 */
struct net_device * dev; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
struct net_device * input_dev; /* 64 8 */
sk_buff_data_t transport_header; /* 72 4 */
sk_buff_data_t network_header; /* 76 4 */
sk_buff_data_t mac_header; /* 80 4 */
/* XXX 4 bytes hole, try to pack */
struct dst_entry * dst; /* 88 8 */
struct sec_path * sp; /* 96 8 */
char cb[48]; /* 104 48 */
/* cacheline 2 boundary (128 bytes) was 24 bytes ago*/
unsigned int len; /* 152 4 */
unsigned int data_len; /* 156 4 */
unsigned int mac_len; /* 160 4 */
union {
__wsum csum; /* 4 */
__u32 csum_offset; /* 4 */
}; /* 164 4 */
__u32 priority; /* 168 4 */
__u8 local_df:1; /* 172 1 */
__u8 cloned:1; /* 172 1 */
__u8 ip_summed:2; /* 172 1 */
__u8 nohdr:1; /* 172 1 */
__u8 nfctinfo:3; /* 172 1 */
__u8 pkt_type:3; /* 173 1 */
__u8 fclone:2; /* 173 1 */
__u8 ipvs_property:1; /* 173 1 */
/* XXX 2 bits hole, try to pack */
__be16 protocol; /* 174 2 */
void (*destructor)(struct sk_buff *); /* 176 8 */
struct nf_conntrack * nfct; /* 184 8 */
/* --- cacheline 3 boundary (192 bytes) --- */
struct sk_buff * nfct_reasm; /* 192 8 */
struct nf_bridge_info *nf_bridge; /* 200 8 */
__u16 tc_index; /* 208 2 */
__u16 tc_verd; /* 210 2 */
dma_cookie_t dma_cookie; /* 212 4 */
__u32 secmark; /* 216 4 */
__u32 mark; /* 220 4 */
unsigned int truesize; /* 224 4 */
atomic_t users; /* 228 4 */
unsigned char * head; /* 232 8 */
unsigned char * data; /* 240 8 */
unsigned char * tail; /* 248 8 */
/* --- cacheline 4 boundary (256 bytes) --- */
unsigned char * end; /* 256 8 */
}; /* size: 264, cachelines: 5 */
/* sum members: 260, holes: 1, sum holes: 4 */
/* bit holes: 1, sum bit holes: 2 bits */
/* last cacheline: 8 bytes */
On 32 bits nothing changes, and pointers continue to be used with the compiler
turning all this abstraction layer into dust. But there are some sk_buff
validation tricks that are now possible, humm... :-)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Renaming skb->h to skb->transport_header, skb->nh to skb->network_header and
skb->mac to skb->mac_header, to match the names of the associated helpers
(skb[_[re]set]_{transport,network,mac}_header).
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
For consistency with all the other skb->h.raw accessors. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
For the quite common 'skb->h.raw - skb->data' sequence. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>