linux/net/core/skbuff.c

2247 lines
55 KiB

[NETFILTER]: Add nf_conntrack subsystem. The existing connection tracking subsystem in netfilter can only handle ipv4. There were basically two choices present to add connection tracking support for ipv6. We could either duplicate all of the ipv4 connection tracking code into an ipv6 counterpart, or (the choice taken by these patches) we could design a generic layer that could handle both ipv4 and ipv6 and thus requiring only one sub-protocol (TCP, UDP, etc.) connection tracking helper module to be written. In fact nf_conntrack is capable of working with any layer 3 protocol. The existing ipv4 specific conntrack code could also not deal with the pecularities of doing connection tracking on ipv6, which is also cured here. For example, these issues include: 1) ICMPv6 handling, which is used for neighbour discovery in ipv6 thus some messages such as these should not participate in connection tracking since effectively they are like ARP messages 2) fragmentation must be handled differently in ipv6, because the simplistic "defrag, connection track and NAT, refrag" (which the existing ipv4 connection tracking does) approach simply isn't feasible in ipv6 3) ipv6 extension header parsing must occur at the correct spots before and after connection tracking decisions, and there were no provisions for this in the existing connection tracking design 4) ipv6 has no need for stateful NAT The ipv4 specific conntrack layer is kept around, until all of the ipv4 specific conntrack helpers are ported over to nf_conntrack and it is feature complete. Once that occurs, the old conntrack stuff will get placed into the feature-removal-schedule and we will fully kill it off 6 months later. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-09 16:38:16 -08:00
[NETFILTER]: Add nf_conntrack subsystem. The existing connection tracking subsystem in netfilter can only handle ipv4. There were basically two choices present to add connection tracking support for ipv6. We could either duplicate all of the ipv4 connection tracking code into an ipv6 counterpart, or (the choice taken by these patches) we could design a generic layer that could handle both ipv4 and ipv6 and thus requiring only one sub-protocol (TCP, UDP, etc.) connection tracking helper module to be written. In fact nf_conntrack is capable of working with any layer 3 protocol. The existing ipv4 specific conntrack code could also not deal with the pecularities of doing connection tracking on ipv6, which is also cured here. For example, these issues include: 1) ICMPv6 handling, which is used for neighbour discovery in ipv6 thus some messages such as these should not participate in connection tracking since effectively they are like ARP messages 2) fragmentation must be handled differently in ipv6, because the simplistic "defrag, connection track and NAT, refrag" (which the existing ipv4 connection tracking does) approach simply isn't feasible in ipv6 3) ipv6 extension header parsing must occur at the correct spots before and after connection tracking decisions, and there were no provisions for this in the existing connection tracking design 4) ipv6 has no need for stateful NAT The ipv4 specific conntrack layer is kept around, until all of the ipv4 specific conntrack helpers are ported over to nf_conntrack and it is feature complete. Once that occurs, the old conntrack stuff will get placed into the feature-removal-schedule and we will fully kill it off 6 months later. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-09 16:38:16 -08:00
[SKBUFF]: Keep track of writable header len of headerless clones Currently NAT (and others) that want to modify cloned skbs copy them, even if in the vast majority of cases its not necessary because the skb is a clone made by TCP and the portion NAT wants to modify is actually writable because TCP release the header reference before cloning. The problem is that there is no clean way for NAT to find out how long the writable header area is, so this patch introduces skb->hdr_len to hold this length. When a headerless skb is cloned skb->hdr_len is set to the current headroom, for regular clones it is copied from the original. A new function skb_clone_writable(skb, len) returns whether the skb is writable up to len bytes from skb->data. To avoid enlarging the skb the mac_len field is reduced to 16 bit and the new hdr_len field is put in the remaining 16 bit. I've done a few rough benchmarks of NAT (not with this exact patch, but a very similar one). As expected it saves huge amounts of system time in case of sendfile, bringing it down to basically the same amount as without NAT, with sendmsg it only helps on loopback, probably because of the large MTU. Transmit a 1GB file using sendfile/sendmsg over eth0/lo with and without NAT: - sendfile eth0, no NAT: sys 0m0.388s - sendfile eth0, NAT: sys 0m1.835s - sendfile eth0: NAT + path: sys 0m0.370s (~ -80%) - sendfile lo, no NAT: sys 0m0.258s - sendfile lo, NAT: sys 0m2.609s - sendfile lo, NAT + patch: sys 0m0.260s (~ -90%) - sendmsg eth0, no NAT: sys 0m2.508s - sendmsg eth0, NAT: sys 0m2.539s - sendmsg eth0, NAT + patch: sys 0m2.445s (no change) - sendmsg lo, no NAT: sys 0m2.151s - sendmsg lo, NAT: sys 0m3.557s - sendmsg lo, NAT + patch: sys 0m2.159s (~ -40%) I expect other users can see a similar performance improvement, packet mangling iptables targets, ipip and ip_gre come to mind .. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-06-25 04:35:20 -07:00
[SK_BUFF]: Use offsets for skb->{mac,network,transport}_header on 64bit architectures 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>
2007-04-10 21:22:35 -07:00
[SK_BUFF]: Use offsets for skb->{mac,network,transport}_header on 64bit architectures 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>
2007-04-10 21:22:35 -07:00
[SK_BUFF]: Use offsets for skb->{mac,network,transport}_header on 64bit architectures 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>
2007-04-10 21:22:35 -07:00
[NET]: Fix net/core/skbuff.c gcc-3.2.3 compilation error Compiling 2.6.22-rc1 with gcc-3.2.3 for i486 fails with: gcc -m32 -Wp,-MD,net/core/.skbuff.o.d -nostdinc -isystem /home/mikpe/pkgs/linux-x86/gnu/lib/gcc-lib/i486-pc-linux-gnu/3.2.3/include -D__KERNEL__ -Iinclude -include include/linux/autoconf.h -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2 -pipe -msoft-float -mregparm=3 -freg-struct-return -mpreferred-stack-boundary=4 -march=i486 -ffreestanding -maccumulate-outgoing-args -DCONFIG_AS_CFI=1 -Iinclude/asm-i386/mach-default -fomit-frame-pointer -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(skbuff)" -D"KBUILD_MODNAME=KBUILD_STR(skbuff)" -c -o net/core/skbuff.o net/core/skbuff.c net/core/skbuff.c:648:1: directives may not be used inside a macro argument net/core/skbuff.c:647:39: unterminated argument list invoking macro "memcpy" net/core/skbuff.c: In function `pskb_expand_head': net/core/skbuff.c:651: `memcpy' undeclared (first use in this function) net/core/skbuff.c:651: (Each undeclared identifier is reported only once net/core/skbuff.c:651: for each function it appears in.) net/core/skbuff.c:651: syntax error before "skb" make[2]: *** [net/core/skbuff.o] Error 1 make[1]: *** [net/core] Error 2 make: *** [net] Error 2 The patch below implements a simple workaround which is to clone the offending memcpy() call and specialise it for the two different scenarios. Other workarounds are of course possible: e.g. bind the varying parameter in a local variable, or use a macro or inline function to perform the varying computation. Signed-off-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-05-19 13:55:25 -07:00
[NET]: Fix net/core/skbuff.c gcc-3.2.3 compilation error Compiling 2.6.22-rc1 with gcc-3.2.3 for i486 fails with: gcc -m32 -Wp,-MD,net/core/.skbuff.o.d -nostdinc -isystem /home/mikpe/pkgs/linux-x86/gnu/lib/gcc-lib/i486-pc-linux-gnu/3.2.3/include -D__KERNEL__ -Iinclude -include include/linux/autoconf.h -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2 -pipe -msoft-float -mregparm=3 -freg-struct-return -mpreferred-stack-boundary=4 -march=i486 -ffreestanding -maccumulate-outgoing-args -DCONFIG_AS_CFI=1 -Iinclude/asm-i386/mach-default -fomit-frame-pointer -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(skbuff)" -D"KBUILD_MODNAME=KBUILD_STR(skbuff)" -c -o net/core/skbuff.o net/core/skbuff.c net/core/skbuff.c:648:1: directives may not be used inside a macro argument net/core/skbuff.c:647:39: unterminated argument list invoking macro "memcpy" net/core/skbuff.c: In function `pskb_expand_head': net/core/skbuff.c:651: `memcpy' undeclared (first use in this function) net/core/skbuff.c:651: (Each undeclared identifier is reported only once net/core/skbuff.c:651: for each function it appears in.) net/core/skbuff.c:651: syntax error before "skb" make[2]: *** [net/core/skbuff.o] Error 1 make[1]: *** [net/core] Error 2 make: *** [net] Error 2 The patch below implements a simple workaround which is to clone the offending memcpy() call and specialise it for the two different scenarios. Other workarounds are of course possible: e.g. bind the varying parameter in a local variable, or use a macro or inline function to perform the varying computation. Signed-off-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-05-19 13:55:25 -07:00
[SKBUFF]: Keep track of writable header len of headerless clones Currently NAT (and others) that want to modify cloned skbs copy them, even if in the vast majority of cases its not necessary because the skb is a clone made by TCP and the portion NAT wants to modify is actually writable because TCP release the header reference before cloning. The problem is that there is no clean way for NAT to find out how long the writable header area is, so this patch introduces skb->hdr_len to hold this length. When a headerless skb is cloned skb->hdr_len is set to the current headroom, for regular clones it is copied from the original. A new function skb_clone_writable(skb, len) returns whether the skb is writable up to len bytes from skb->data. To avoid enlarging the skb the mac_len field is reduced to 16 bit and the new hdr_len field is put in the remaining 16 bit. I've done a few rough benchmarks of NAT (not with this exact patch, but a very similar one). As expected it saves huge amounts of system time in case of sendfile, bringing it down to basically the same amount as without NAT, with sendmsg it only helps on loopback, probably because of the large MTU. Transmit a 1GB file using sendfile/sendmsg over eth0/lo with and without NAT: - sendfile eth0, no NAT: sys 0m0.388s - sendfile eth0, NAT: sys 0m1.835s - sendfile eth0: NAT + path: sys 0m0.370s (~ -80%) - sendfile lo, no NAT: sys 0m0.258s - sendfile lo, NAT: sys 0m2.609s - sendfile lo, NAT + patch: sys 0m0.260s (~ -90%) - sendmsg eth0, no NAT: sys 0m2.508s - sendmsg eth0, NAT: sys 0m2.539s - sendmsg eth0, NAT + patch: sys 0m2.445s (no change) - sendmsg lo, no NAT: sys 0m2.151s - sendmsg lo, NAT: sys 0m3.557s - sendmsg lo, NAT + patch: sys 0m2.159s (~ -40%) I expect other users can see a similar performance improvement, packet mangling iptables targets, ipip and ip_gre come to mind .. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-06-25 04:35:20 -07:00
[IPv4/IPv6]: UFO Scatter-gather approach Attached is kernel patch for UDP Fragmentation Offload (UFO) feature. 1. This patch incorporate the review comments by Jeff Garzik. 2. Renamed USO as UFO (UDP Fragmentation Offload) 3. udp sendfile support with UFO This patches uses scatter-gather feature of skb to generate large UDP datagram. Below is a "how-to" on changes required in network device driver to use the UFO interface. UDP Fragmentation Offload (UFO) Interface: ------------------------------------------- UFO is a feature wherein the Linux kernel network stack will offload the IP fragmentation functionality of large UDP datagram to hardware. This will reduce the overhead of stack in fragmenting the large UDP datagram to MTU sized packets 1) Drivers indicate their capability of UFO using dev->features |= NETIF_F_UFO | NETIF_F_HW_CSUM | NETIF_F_SG NETIF_F_HW_CSUM is required for UFO over ipv6. 2) UFO packet will be submitted for transmission using driver xmit routine. UFO packet will have a non-zero value for "skb_shinfo(skb)->ufo_size" skb_shinfo(skb)->ufo_size will indicate the length of data part in each IP fragment going out of the adapter after IP fragmentation by hardware. skb->data will contain MAC/IP/UDP header and skb_shinfo(skb)->frags[] contains the data payload. The skb->ip_summed will be set to CHECKSUM_HW indicating that hardware has to do checksum calculation. Hardware should compute the UDP checksum of complete datagram and also ip header checksum of each fragmented IP packet. For IPV6 the UFO provides the fragment identification-id in skb_shinfo(skb)->ip6_frag_id. The adapter should use this ID for generating IPv6 fragments. Signed-off-by: Ananda Raju <ananda.raju@neterion.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (forwarded) Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-10-18 15:46:41 -07:00
[IPv4/IPv6]: UFO Scatter-gather approach Attached is kernel patch for UDP Fragmentation Offload (UFO) feature. 1. This patch incorporate the review comments by Jeff Garzik. 2. Renamed USO as UFO (UDP Fragmentation Offload) 3. udp sendfile support with UFO This patches uses scatter-gather feature of skb to generate large UDP datagram. Below is a "how-to" on changes required in network device driver to use the UFO interface. UDP Fragmentation Offload (UFO) Interface: ------------------------------------------- UFO is a feature wherein the Linux kernel network stack will offload the IP fragmentation functionality of large UDP datagram to hardware. This will reduce the overhead of stack in fragmenting the large UDP datagram to MTU sized packets 1) Drivers indicate their capability of UFO using dev->features |= NETIF_F_UFO | NETIF_F_HW_CSUM | NETIF_F_SG NETIF_F_HW_CSUM is required for UFO over ipv6. 2) UFO packet will be submitted for transmission using driver xmit routine. UFO packet will have a non-zero value for "skb_shinfo(skb)->ufo_size" skb_shinfo(skb)->ufo_size will indicate the length of data part in each IP fragment going out of the adapter after IP fragmentation by hardware. skb->data will contain MAC/IP/UDP header and skb_shinfo(skb)->frags[] contains the data payload. The skb->ip_summed will be set to CHECKSUM_HW indicating that hardware has to do checksum calculation. Hardware should compute the UDP checksum of complete datagram and also ip header checksum of each fragmented IP packet. For IPV6 the UFO provides the fragment identification-id in skb_shinfo(skb)->ip6_frag_id. The adapter should use this ID for generating IPv6 fragments. Signed-off-by: Ananda Raju <ananda.raju@neterion.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (forwarded) Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-10-18 15:46:41 -07:00
[IPv4/IPv6]: UFO Scatter-gather approach Attached is kernel patch for UDP Fragmentation Offload (UFO) feature. 1. This patch incorporate the review comments by Jeff Garzik. 2. Renamed USO as UFO (UDP Fragmentation Offload) 3. udp sendfile support with UFO This patches uses scatter-gather feature of skb to generate large UDP datagram. Below is a "how-to" on changes required in network device driver to use the UFO interface. UDP Fragmentation Offload (UFO) Interface: ------------------------------------------- UFO is a feature wherein the Linux kernel network stack will offload the IP fragmentation functionality of large UDP datagram to hardware. This will reduce the overhead of stack in fragmenting the large UDP datagram to MTU sized packets 1) Drivers indicate their capability of UFO using dev->features |= NETIF_F_UFO | NETIF_F_HW_CSUM | NETIF_F_SG NETIF_F_HW_CSUM is required for UFO over ipv6. 2) UFO packet will be submitted for transmission using driver xmit routine. UFO packet will have a non-zero value for "skb_shinfo(skb)->ufo_size" skb_shinfo(skb)->ufo_size will indicate the length of data part in each IP fragment going out of the adapter after IP fragmentation by hardware. skb->data will contain MAC/IP/UDP header and skb_shinfo(skb)->frags[] contains the data payload. The skb->ip_summed will be set to CHECKSUM_HW indicating that hardware has to do checksum calculation. Hardware should compute the UDP checksum of complete datagram and also ip header checksum of each fragmented IP packet. For IPV6 the UFO provides the fragment identification-id in skb_shinfo(skb)->ip6_frag_id. The adapter should use this ID for generating IPv6 fragments. Signed-off-by: Ananda Raju <ananda.raju@neterion.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (forwarded) Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-10-18 15:46:41 -07:00