linux-toradex.git/include/net/ip_tunnels.h, branch v6.5-rc4 Linux kernel for Apalis and Colibri modules Daniel Borkmann says: 2023-04-13T23:43:38+00:00 Jakub Kicinski kuba@kernel.org 2023-04-13T23:11:22+00:00 c2865b1122595e69e7df52d01f7f02338b8babca ==================== pull-request: bpf-next 2023-04-13 We've added 260 non-merge commits during the last 36 day(s) which contain a total of 356 files changed, 21786 insertions(+), 11275 deletions(-). The main changes are: 1) Rework BPF verifier log behavior and implement it as a rotating log by default with the option to retain old-style fixed log behavior, from Andrii Nakryiko. 2) Adds support for using {FOU,GUE} encap with an ipip device operating in collect_md mode and add a set of BPF kfuncs for controlling encap params, from Christian Ehrig. 3) Allow BPF programs to detect at load time whether a particular kfunc exists or not, and also add support for this in light skeleton, from Alexei Starovoitov. 4) Optimize hashmap lookups when key size is multiple of 4, from Anton Protopopov. 5) Enable RCU semantics for task BPF kptrs and allow referenced kptr tasks to be stored in BPF maps, from David Vernet. 6) Add support for stashing local BPF kptr into a map value via bpf_kptr_xchg(). This is useful e.g. for rbtree node creation for new cgroups, from Dave Marchevsky. 7) Fix BTF handling of is_int_ptr to skip modifiers to work around tracing issues where a program cannot be attached, from Feng Zhou. 8) Migrate a big portion of test_verifier unit tests over to test_progs -a verifier_* via inline asm to ease {read,debug}ability, from Eduard Zingerman. 9) Several updates to the instruction-set.rst documentation which is subject to future IETF standardization (https://lwn.net/Articles/926882/), from Dave Thaler. 10) Fix BPF verifier in the __reg_bound_offset's 64->32 tnum sub-register known bits information propagation, from Daniel Borkmann. 11) Add skb bitfield compaction work related to BPF with the overall goal to make more of the sk_buff bits optional, from Jakub Kicinski. 12) BPF selftest cleanups for build id extraction which stand on its own from the upcoming integration work of build id into struct file object, from Jiri Olsa. 13) Add fixes and optimizations for xsk descriptor validation and several selftest improvements for xsk sockets, from Kal Conley. 14) Add BPF links for struct_ops and enable switching implementations of BPF TCP cong-ctls under a given name by replacing backing struct_ops map, from Kui-Feng Lee. 15) Remove a misleading BPF verifier env->bypass_spec_v1 check on variable offset stack read as earlier Spectre checks cover this, from Luis Gerhorst. 16) Fix issues in copy_from_user_nofault() for BPF and other tracers to resemble copy_from_user_nmi() from safety PoV, from Florian Lehner and Alexei Starovoitov. 17) Add --json-summary option to test_progs in order for CI tooling to ease parsing of test results, from Manu Bretelle. 18) Batch of improvements and refactoring to prep for upcoming bpf_local_storage conversion to bpf_mem_cache_{alloc,free} allocator, from Martin KaFai Lau. 19) Improve bpftool's visual program dump which produces the control flow graph in a DOT format by adding C source inline annotations, from Quentin Monnet. 20) Fix attaching fentry/fexit/fmod_ret/lsm to modules by extracting the module name from BTF of the target and searching kallsyms of the correct module, from Viktor Malik. 21) Improve BPF verifier handling of '<const> <cond> <non_const>' to better detect whether in particular jmp32 branches are taken, from Yonghong Song. 22) Allow BPF TCP cong-ctls to write app_limited of struct tcp_sock. A built-in cc or one from a kernel module is already able to write to app_limited, from Yixin Shen. Conflicts: Documentation/bpf/bpf_devel_QA.rst b7abcd9c656b ("bpf, doc: Link to submitting-patches.rst for general patch submission info") 0f10f647f455 ("bpf, docs: Use internal linking for link to netdev subsystem doc") https://lore.kernel.org/all/20230307095812.236eb1be@canb.auug.org.au/ include/net/ip_tunnels.h bc9d003dc48c3 ("ip_tunnel: Preserve pointer const in ip_tunnel_info_opts") ac931d4cdec3d ("ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices") https://lore.kernel.org/all/20230413161235.4093777-1-broonie@kernel.org/ net/bpf/test_run.c e5995bc7e2ba ("bpf, test_run: fix crashes due to XDP frame overwriting/corruption") 294635a8165a ("bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES") https://lore.kernel.org/all/20230320102619.05b80a98@canb.auug.org.au/ ==================== Link: https://lore.kernel.org/r/20230413191525.7295-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
====================
pull-request: bpf-next 2023-04-13

We've added 260 non-merge commits during the last 36 day(s) which contain
a total of 356 files changed, 21786 insertions(+), 11275 deletions(-).

The main changes are:

1) Rework BPF verifier log behavior and implement it as a rotating log
   by default with the option to retain old-style fixed log behavior,
   from Andrii Nakryiko.

2) Adds support for using {FOU,GUE} encap with an ipip device operating
   in collect_md mode and add a set of BPF kfuncs for controlling encap
   params, from Christian Ehrig.

3) Allow BPF programs to detect at load time whether a particular kfunc
   exists or not, and also add support for this in light skeleton,
   from Alexei Starovoitov.

4) Optimize hashmap lookups when key size is multiple of 4,
   from Anton Protopopov.

5) Enable RCU semantics for task BPF kptrs and allow referenced kptr
   tasks to be stored in BPF maps, from David Vernet.

6) Add support for stashing local BPF kptr into a map value via
   bpf_kptr_xchg(). This is useful e.g. for rbtree node creation
   for new cgroups, from Dave Marchevsky.

7) Fix BTF handling of is_int_ptr to skip modifiers to work around
   tracing issues where a program cannot be attached, from Feng Zhou.

8) Migrate a big portion of test_verifier unit tests over to
   test_progs -a verifier_* via inline asm to ease {read,debug}ability,
   from Eduard Zingerman.

9) Several updates to the instruction-set.rst documentation
   which is subject to future IETF standardization
   (https://lwn.net/Articles/926882/), from Dave Thaler.

10) Fix BPF verifier in the __reg_bound_offset's 64->32 tnum sub-register
    known bits information propagation, from Daniel Borkmann.

11) Add skb bitfield compaction work related to BPF with the overall goal
    to make more of the sk_buff bits optional, from Jakub Kicinski.

12) BPF selftest cleanups for build id extraction which stand on its own
    from the upcoming integration work of build id into struct file object,
    from Jiri Olsa.

13) Add fixes and optimizations for xsk descriptor validation and several
    selftest improvements for xsk sockets, from Kal Conley.

14) Add BPF links for struct_ops and enable switching implementations
    of BPF TCP cong-ctls under a given name by replacing backing
    struct_ops map, from Kui-Feng Lee.

15) Remove a misleading BPF verifier env->bypass_spec_v1 check on variable
    offset stack read as earlier Spectre checks cover this,
    from Luis Gerhorst.

16) Fix issues in copy_from_user_nofault() for BPF and other tracers
    to resemble copy_from_user_nmi() from safety PoV, from Florian Lehner
    and Alexei Starovoitov.

17) Add --json-summary option to test_progs in order for CI tooling to
    ease parsing of test results, from Manu Bretelle.

18) Batch of improvements and refactoring to prep for upcoming
    bpf_local_storage conversion to bpf_mem_cache_{alloc,free} allocator,
    from Martin KaFai Lau.

19) Improve bpftool's visual program dump which produces the control
    flow graph in a DOT format by adding C source inline annotations,
    from Quentin Monnet.

20) Fix attaching fentry/fexit/fmod_ret/lsm to modules by extracting
    the module name from BTF of the target and searching kallsyms of
    the correct module, from Viktor Malik.

21) Improve BPF verifier handling of '<const> <cond> <non_const>'
    to better detect whether in particular jmp32 branches are taken,
    from Yonghong Song.

22) Allow BPF TCP cong-ctls to write app_limited of struct tcp_sock.
    A built-in cc or one from a kernel module is already able to write
    to app_limited, from Yixin Shen.

Conflicts:

Documentation/bpf/bpf_devel_QA.rst
  b7abcd9c656b ("bpf, doc: Link to submitting-patches.rst for general patch submission info")
  0f10f647f455 ("bpf, docs: Use internal linking for link to netdev subsystem doc")
https://lore.kernel.org/all/20230307095812.236eb1be@canb.auug.org.au/

include/net/ip_tunnels.h
  bc9d003dc48c3 ("ip_tunnel: Preserve pointer const in ip_tunnel_info_opts")
  ac931d4cdec3d ("ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices")
https://lore.kernel.org/all/20230413161235.4093777-1-broonie@kernel.org/

net/bpf/test_run.c
  e5995bc7e2ba ("bpf, test_run: fix crashes due to XDP frame overwriting/corruption")
  294635a8165a ("bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES")
https://lore.kernel.org/all/20230320102619.05b80a98@canb.auug.org.au/
====================

Link: https://lore.kernel.org/r/20230413191525.7295-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices 2023-04-12T23:40:39+00:00 Christian Ehrig cehrig@cloudflare.com 2023-04-07T13:38:53+00:00 ac931d4cdec3df8b6eac3bc40a6871123021f078 Today ipip devices in collect-metadata mode don't allow for sending FOU or GUE encapsulated packets. This patch lifts the restriction by adding a struct ip_tunnel_encap to the tunnel metadata. On the egress path, the members of this struct can be set by the bpf_skb_set_fou_encap kfunc via a BPF tc-hook. Instead of dropping packets wishing to use additional UDP encapsulation, ip_md_tunnel_xmit now evaluates the contents of this struct and adds the corresponding FOU or GUE header. Furthermore, it is making sure that additional header bytes are taken into account for PMTU discovery. On the ingress path, an ipip device in collect-metadata mode will fill this struct and a BPF tc-hook can obtain the information via a call to the bpf_skb_get_fou_encap kfunc. The minor change to ip_tunnel_encap, which now takes a pointer to struct ip_tunnel_encap instead of struct ip_tunnel, allows us to control FOU encap type and parameters on a per packet-level. Signed-off-by: Christian Ehrig <cehrig@cloudflare.com> Link: https://lore.kernel.org/r/cfea47de655d0f870248abf725932f851b53960a.1680874078.git.cehrig@cloudflare.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> 
Today ipip devices in collect-metadata mode don't allow for sending FOU
or GUE encapsulated packets. This patch lifts the restriction by adding
a struct ip_tunnel_encap to the tunnel metadata.

On the egress path, the members of this struct can be set by the
bpf_skb_set_fou_encap kfunc via a BPF tc-hook. Instead of dropping packets
wishing to use additional UDP encapsulation, ip_md_tunnel_xmit now
evaluates the contents of this struct and adds the corresponding FOU or
GUE header. Furthermore, it is making sure that additional header bytes
are taken into account for PMTU discovery.

On the ingress path, an ipip device in collect-metadata mode will fill this
struct and a BPF tc-hook can obtain the information via a call to the
bpf_skb_get_fou_encap kfunc.

The minor change to ip_tunnel_encap, which now takes a pointer to
struct ip_tunnel_encap instead of struct ip_tunnel, allows us to control
FOU encap type and parameters on a per packet-level.

Signed-off-by: Christian Ehrig <cehrig@cloudflare.com>
Link: https://lore.kernel.org/r/cfea47de655d0f870248abf725932f851b53960a.1680874078.git.cehrig@cloudflare.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
ip_tunnel: Preserve pointer const in ip_tunnel_info_opts 2023-03-18T05:41:16+00:00 Gavin Li gavinl@nvidia.com 2023-03-16T07:07:57+00:00 bc9d003dc48c381763c3a6309bfc5eecf9962b9c Change ip_tunnel_info_opts( ) from static function to macro to cast return value and preserve the const-ness of the pointer. Signed-off-by: Gavin Li <gavinl@nvidia.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Change ip_tunnel_info_opts( ) from static function to macro to cast return
value and preserve the const-ness of the pointer.

Signed-off-by: Gavin Li <gavinl@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: Add helper function to parse netlink msg of ip_tunnel_parm 2022-10-03T06:59:06+00:00 Liu Jian liujian56@huawei.com 2022-09-29T13:52:03+00:00 b86fca800a6a3d439c454b462f7f067a18234e60 Add ip_tunnel_netlink_parms to parse netlink msg of ip_tunnel_parm. Reduces duplicate code, no actual functional changes. Signed-off-by: Liu Jian <liujian56@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Add ip_tunnel_netlink_parms to parse netlink msg of ip_tunnel_parm.
Reduces duplicate code, no actual functional changes.

Signed-off-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: Add helper function to parse netlink msg of ip_tunnel_encap 2022-10-03T06:59:06+00:00 Liu Jian liujian56@huawei.com 2022-09-29T13:52:02+00:00 537dd2d9fb9f4aa7939fb4fcf552ebe4f497bd7e Add ip_tunnel_netlink_encap_parms to parse netlink msg of ip_tunnel_encap. Reduces duplicate code, no actual functional changes. Signed-off-by: Liu Jian <liujian56@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Add ip_tunnel_netlink_encap_parms to parse netlink msg of ip_tunnel_encap.
Reduces duplicate code, no actual functional changes.

Signed-off-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_tunnel: Respect tunnel key's "flow_flags" in IP tunnels 2022-08-18T19:18:28+00:00 Eyal Birger eyal.birger@gmail.com 2022-08-18T07:41:18+00:00 7ec9fce4b31604f8415136a4c07f7dc8ad431aec Commit 451ef36bd229 ("ip_tunnels: Add new flow flags field to ip_tunnel_key") added a "flow_flags" member to struct ip_tunnel_key which was later used by the commit in the fixes tag to avoid dropping packets with sources that aren't locally configured when set in bpf_set_tunnel_key(). VXLAN and GENEVE were made to respect this flag, ip tunnels like IPIP and GRE were not. This commit fixes this omission by making ip_tunnel_init_flow() receive the flow flags from the tunnel key in the relevant collect_md paths. Fixes: b8fff748521c ("bpf: Set flow flag to allow any source IP in bpf_tunnel_key") Signed-off-by: Eyal Birger <eyal.birger@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Paul Chaignon <paul@isovalent.com> Link: https://lore.kernel.org/bpf/20220818074118.726639-1-eyal.birger@gmail.com 
Commit 451ef36bd229 ("ip_tunnels: Add new flow flags field to ip_tunnel_key")
added a "flow_flags" member to struct ip_tunnel_key which was later used by
the commit in the fixes tag to avoid dropping packets with sources that
aren't locally configured when set in bpf_set_tunnel_key().

VXLAN and GENEVE were made to respect this flag, ip tunnels like IPIP and GRE
were not.

This commit fixes this omission by making ip_tunnel_init_flow() receive
the flow flags from the tunnel key in the relevant collect_md paths.

Fixes: b8fff748521c ("bpf: Set flow flag to allow any source IP in bpf_tunnel_key")
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Paul Chaignon <paul@isovalent.com>
Link: https://lore.kernel.org/bpf/20220818074118.726639-1-eyal.birger@gmail.com
ip_tunnels: Add new flow flags field to ip_tunnel_key 2022-07-26T10:43:16+00:00 Paul Chaignon paul@isovalent.com 2022-07-25T14:31:37+00:00 451ef36bd229f8aa329cb2258a859b4c636d08ef This commit extends the ip_tunnel_key struct with a new field for the flow flags, to pass them to the route lookups. This new field will be populated and used in subsequent commits. Signed-off-by: Paul Chaignon <paul@isovalent.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/f8bfd4983bd06685a59b1e3ba76ca27496f51ef3.1658759380.git.paul@isovalent.com 
This commit extends the ip_tunnel_key struct with a new field for the
flow flags, to pass them to the route lookups. This new field will be
populated and used in subsequent commits.

Signed-off-by: Paul Chaignon <paul@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/f8bfd4983bd06685a59b1e3ba76ca27496f51ef3.1658759380.git.paul@isovalent.com
ip_tunnels: allow VXLAN/GENEVE to inherit TOS/TTL from VLAN 2022-07-23T04:47:28+00:00 Matthias May matthias.may@westermo.com 2022-07-21T20:27:19+00:00 7074732c8faee201a245a6f983008a5789c0be33 The current code allows for VXLAN and GENEVE to inherit the TOS respective the TTL when skb-protocol is ETH_P_IP or ETH_P_IPV6. However when the payload is VLAN encapsulated, then this inheriting does not work, because the visible skb-protocol is of type ETH_P_8021Q or ETH_P_8021AD. Instead of skb->protocol use skb_protocol(). Signed-off-by: Matthias May <matthias.may@westermo.com> Link: https://lore.kernel.org/r/20220721202718.10092-1-matthias.may@westermo.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
The current code allows for VXLAN and GENEVE to inherit the TOS
respective the TTL when skb-protocol is ETH_P_IP or ETH_P_IPV6.
However when the payload is VLAN encapsulated, then this inheriting
does not work, because the visible skb-protocol is of type
ETH_P_8021Q or ETH_P_8021AD.

Instead of skb->protocol use skb_protocol().

Signed-off-by: Matthias May <matthias.may@westermo.com>
Link: https://lore.kernel.org/r/20220721202718.10092-1-matthias.may@westermo.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: adopt u64_stats_t in struct pcpu_sw_netstats 2022-06-10T04:53:11+00:00 Eric Dumazet edumazet@google.com 2022-06-08T15:46:37+00:00 9962acefbcb92736c268aafe5f52200948f60f3e As explained in commit 316580b69d0a ("u64_stats: provide u64_stats_t type") we should use u64_stats_t and related accessors to avoid load/store tearing. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
As explained in commit 316580b69d0a ("u64_stats: provide u64_stats_t type")
we should use u64_stats_t and related accessors to avoid load/store tearing.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ip_gre, ip6_gre: Fix race condition on o_seqno in collect_md mode 2022-04-25T10:40:45+00:00 Peilin Ye peilin.ye@bytedance.com 2022-04-21T22:09:02+00:00 31c417c948d7f6909cb63f0ac3298f3c38f8ce20 As pointed out by Jakub Kicinski, currently using TUNNEL_SEQ in collect_md mode is racy for [IP6]GRE[TAP] devices. Consider the following sequence of events: 1. An [IP6]GRE[TAP] device is created in collect_md mode using "ip link add ... external". "ip" ignores "[o]seq" if "external" is specified, so TUNNEL_SEQ is off, and the device is marked as NETIF_F_LLTX (i.e. it uses lockless TX); 2. Someone sets TUNNEL_SEQ on outgoing skb's, using e.g. bpf_skb_set_tunnel_key() in an eBPF program attached to this device; 3. gre_fb_xmit() or __gre6_xmit() processes these skb's: gre_build_header(skb, tun_hlen, flags, protocol, tunnel_id_to_key32(tun_info->key.tun_id), (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0); ^^^^^^^^^^^^^^^^^ Since we are not using the TX lock (&txq->_xmit_lock), multiple CPUs may try to do this tunnel->o_seqno++ in parallel, which is racy. Fix it by making o_seqno atomic_t. As mentioned by Eric Dumazet in commit b790e01aee74 ("ip_gre: lockless xmit"), making o_seqno atomic_t increases "chance for packets being out of order at receiver" when NETIF_F_LLTX is on. Maybe a better fix would be: 1. Do not ignore "oseq" in external mode. Users MUST specify "oseq" if they want the kernel to allow sequencing of outgoing packets; 2. Reject all outgoing TUNNEL_SEQ packets if the device was not created with "oseq". Unfortunately, that would break userspace. We could now make [IP6]GRE[TAP] devices always NETIF_F_LLTX, but let us do it in separate patches to keep this fix minimal. Suggested-by: Jakub Kicinski <kuba@kernel.org> Fixes: 77a5196a804e ("gre: add sequence number for collect md mode.") Signed-off-by: Peilin Ye <peilin.ye@bytedance.com> Acked-by: William Tu <u9012063@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
As pointed out by Jakub Kicinski, currently using TUNNEL_SEQ in
collect_md mode is racy for [IP6]GRE[TAP] devices.  Consider the
following sequence of events:

1. An [IP6]GRE[TAP] device is created in collect_md mode using "ip link
   add ... external".  "ip" ignores "[o]seq" if "external" is specified,
   so TUNNEL_SEQ is off, and the device is marked as NETIF_F_LLTX (i.e.
   it uses lockless TX);
2. Someone sets TUNNEL_SEQ on outgoing skb's, using e.g.
   bpf_skb_set_tunnel_key() in an eBPF program attached to this device;
3. gre_fb_xmit() or __gre6_xmit() processes these skb's:

	gre_build_header(skb, tun_hlen,
			 flags, protocol,
			 tunnel_id_to_key32(tun_info->key.tun_id),
			 (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++)
					      : 0);   ^^^^^^^^^^^^^^^^^

Since we are not using the TX lock (&txq->_xmit_lock), multiple CPUs may
try to do this tunnel->o_seqno++ in parallel, which is racy.  Fix it by
making o_seqno atomic_t.

As mentioned by Eric Dumazet in commit b790e01aee74 ("ip_gre: lockless
xmit"), making o_seqno atomic_t increases "chance for packets being out
of order at receiver" when NETIF_F_LLTX is on.

Maybe a better fix would be:

1. Do not ignore "oseq" in external mode.  Users MUST specify "oseq" if
   they want the kernel to allow sequencing of outgoing packets;
2. Reject all outgoing TUNNEL_SEQ packets if the device was not created
   with "oseq".

Unfortunately, that would break userspace.

We could now make [IP6]GRE[TAP] devices always NETIF_F_LLTX, but let us
do it in separate patches to keep this fix minimal.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Fixes: 77a5196a804e ("gre: add sequence number for collect md mode.")
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Acked-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>