lwn.git/net/ipv4/fib_semantics.c, branch v5.6-rc7

ipv4: Add "offload" and "trap" indications to routes

2020-01-15T02:53:35+00:00

When performing L3 offload, routes and nexthops are usually programmed into two different tables in the underlying device. Therefore, the fact that a nexthop resides in hardware does not necessarily mean that all the associated routes also reside in hardware and vice-versa. While the kernel can signal to user space the presence of a nexthop in hardware (via 'RTNH_F_OFFLOAD'), it does not have a corresponding flag for routes. In addition, the fact that a route resides in hardware does not necessarily mean that the traffic is offloaded. For example, unreachable routes (i.e., 'RTN_UNREACHABLE') are programmed to trap packets to the CPU so that the kernel will be able to generate the appropriate ICMP error packet. This patch adds an "offload" and "trap" indications to IPv4 routes, so that users will have better visibility into the offload process. 'struct fib_alias' is extended with two new fields that indicate if the route resides in hardware or not and if it is offloading traffic from the kernel or trapping packets to it. Note that the new fields are added in the 6 bytes hole and therefore the struct still fits in a single cache line [1]. Capable drivers are expected to invoke fib_alias_hw_flags_set() with the route's key in order to set the flags. The indications are dumped to user space via a new flags (i.e., 'RTM_F_OFFLOAD' and 'RTM_F_TRAP') in the 'rtm_flags' field in the ancillary header. v2: * Make use of 'struct fib_rt_info' in fib_alias_hw_flags_set() [1] struct fib_alias { struct hlist_node fa_list; /* 0 16 */ struct fib_info * fa_info; /* 16 8 */ u8 fa_tos; /* 24 1 */ u8 fa_type; /* 25 1 */ u8 fa_state; /* 26 1 */ u8 fa_slen; /* 27 1 */ u32 tb_id; /* 28 4 */ s16 fa_default; /* 32 2 */ u8 offload:1; /* 34: 0 1 */ u8 trap:1; /* 34: 1 1 */ u8 unused:6; /* 34: 2 1 */ /* XXX 5 bytes hole, try to pack */ struct callback_head rcu __attribute__((__aligned__(8))); /* 40 16 */ /* size: 56, cachelines: 1, members: 12 */ /* sum members: 50, holes: 1, sum holes: 5 */ /* sum bitfield members: 8 bits (1 bytes) */ /* forced alignments: 1, forced holes: 1, sum forced holes: 5 */ /* last cacheline: 56 bytes */ } __attribute__((__aligned__(8))); Signed-off-by: Ido Schimmel Reviewed-by: David Ahern Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller

ipv4: Encapsulate function arguments in a struct

2020-01-15T02:53:35+00:00

fib_dump_info() is used to prepare RTM_{NEW,DEL}ROUTE netlink messages using the passed arguments. Currently, the function takes 11 arguments, 6 of which are attributes of the route being dumped (e.g., prefix, TOS). The next patch will need the function to also dump to user space an indication if the route is present in hardware or not. Instead of passing yet another argument, change the function to take a struct containing the different route attributes. v2: * Name last argument of fib_dump_info() * Move 'struct fib_rt_info' to include/net/ip_fib.h so that it could later be passed to fib_alias_hw_flags_set() Signed-off-by: Ido Schimmel Reviewed-by: David Ahern Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller

ipv4: Fix table id reference in fib_sync_down_addr

2019-11-08T00:14:36+00:00

Hendrik reported routes in the main table using source address are not removed when the address is removed. The problem is that fib_sync_down_addr does not account for devices in the default VRF which are associated with the main table. Fix by updating the table id reference. Fixes: 5a56a0b3a45d ("net: Don't delete routes in different VRFs") Reported-by: Hendrik Donner Signed-off-by: David Ahern Signed-off-by: David S. Miller

net: Properly update v4 routes with v6 nexthop

2019-09-05T10:35:58+00:00

When creating a v4 route that uses a v6 nexthop from a nexthop group. Allow the kernel to properly send the nexthop as v6 via the RTA_VIA attribute. Broken behavior: $ ip nexthop add via fe80::9 dev eth0 $ ip nexthop show id 1 via fe80::9 dev eth0 scope link $ ip route add 4.5.6.7/32 nhid 1 $ ip route show default via 10.0.2.2 dev eth0 4.5.6.7 nhid 1 via 254.128.0.0 dev eth0 10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15 $ Fixed behavior: $ ip nexthop add via fe80::9 dev eth0 $ ip nexthop show id 1 via fe80::9 dev eth0 scope link $ ip route add 4.5.6.7/32 nhid 1 $ ip route show default via 10.0.2.2 dev eth0 4.5.6.7 nhid 1 via inet6 fe80::9 dev eth0 10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15 $ v2, v3: Addresses code review comments from David Ahern Fixes: dcb1ecb50edf (“ipv4: Prepare for fib6_nh from a nexthop object”) Signed-off-by: Donald Sharp Reviewed-by: David Ahern Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2019-06-18T03:20:36+00:00

Honestly all the conflicts were simple overlapping changes, nothing really interesting to report. Signed-off-by: David S. Miller

ipv4: Optimization for fib_info lookup with nexthops

2019-06-10T17:44:57+00:00

Be optimistic about re-using a fib_info when nexthop id is given and the route does not use metrics. Avoids a memory allocation which in most cases is expected to be freed anyways. Signed-off-by: David Ahern Signed-off-by: David S. Miller

ipv4: Allow routes to use nexthop objects

2019-06-10T17:44:56+00:00

Add support for RTA_NH_ID attribute to allow a user to specify a nexthop id to use with a route. fc_nh_id is added to fib_config to hold the value passed in the RTA_NH_ID attribute. If a nexthop id is given, the gateway, device, encap and multipath attributes can not be set. Update fib_nh_match to check ids on a route delete. Signed-off-by: David Ahern Signed-off-by: David S. Miller

net: ipv4: fib_semantics: fix uninitialized variable

2019-06-09T19:47:30+00:00

fix an uninitialized variable: CC net/ipv4/fib_semantics.o net/ipv4/fib_semantics.c: In function 'fib_check_nh_v4_gw': net/ipv4/fib_semantics.c:1027:12: warning: 'err' may be used uninitialized in this function [-Wmaybe-uninitialized] if (!tbl || err) { ^~ Signed-off-by: Enrico Weigelt Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2019-06-07T18:00:14+00:00

Some ISDN files that got removed in net-next had some changes done in mainline, take the removals. Signed-off-by: David S. Miller

net: ipv4: drop unneeded likely() call around IS_ERR()

2019-06-05T23:57:23+00:00

IS_ERR() already calls unlikely(), so this extra unlikely() call around IS_ERR() is not needed. Signed-off-by: Enrico Weigelt Signed-off-by: David S. Miller