From 55870dfe7f8b1d14c4b52fb689f6d91cbf28a60c Mon Sep 17 00:00:00 2001 From: David Ahern Date: Wed, 13 Feb 2019 15:56:30 -0800 Subject: [PATCH] Improve batch and dump times by caching link lookups ip route uses ll_name_to_index and ll_index_to_name to convert between device names and indices. At the moment both use for the ioctl based glibc functions if_nametoindex and if_indextoname and does not cache the result. When using a batch file or dumping large number of routes this means the same device lookups can be done repeatedly adding unnecessary overhead (socket + ioctl + close for each device lookup). Add a new function, ll_link_get, to send a netlink based RTM_GETLINK. If successful, cache the result in idx_head and name_head so future lookups can re-use the entry. Update ll_name_to_index and ll_index_to_name to use ll_link_get and only fallback to the glibc functions if it fails. With this change the time to install 720,022 routes with 2 ecmp nexthops where the nexthop device is given is reduced from 31.4 seconds to 19.2 seconds. A dump of those routes drops from 13.3 to 2.8 seconds. Signed-off-by: David Ahern --- lib/ll_map.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 51 insertions(+), 1 deletion(-) diff --git a/lib/ll_map.c b/lib/ll_map.c index 8e8a0b1e..2d7b65dc 100644 --- a/lib/ll_map.c +++ b/lib/ll_map.c @@ -152,6 +152,48 @@ static unsigned int ll_idx_a2n(const char *name) return idx; } +static int ll_link_get(const char *name, int index) +{ + struct { + struct nlmsghdr n; + struct ifinfomsg ifm; + char buf[1024]; + } req = { + .n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)), + .n.nlmsg_flags = NLM_F_REQUEST, + .n.nlmsg_type = RTM_GETLINK, + .ifm.ifi_index = index, + }; + __u32 filt_mask = RTEXT_FILTER_VF | RTEXT_FILTER_SKIP_STATS; + struct rtnl_handle rth = {}; + struct nlmsghdr *answer; + int rc = 0; + + if (rtnl_open(&rth, 0) < 0) + return 0; + + addattr32(&req.n, sizeof(req), IFLA_EXT_MASK, filt_mask); + if (name) + addattr_l(&req.n, sizeof(req), IFLA_IFNAME, name, + strlen(name) + 1); + + if (rtnl_talk(&rth, &req.n, &answer) < 0) + goto out; + + /* add entry to cache */ + rc = ll_remember_index(answer, NULL); + if (!rc) { + struct ifinfomsg *ifm = NLMSG_DATA(answer); + + rc = ifm->ifi_index; + } + + free(answer); +out: + rtnl_close(&rth); + return rc; +} + const char *ll_index_to_name(unsigned int idx) { static char buf[IFNAMSIZ]; @@ -164,6 +206,12 @@ const char *ll_index_to_name(unsigned int idx) if (im) return im->name; + if (ll_link_get(NULL, idx) == idx) { + im = ll_get_by_index(idx); + if (im) + return im->name; + } + if (if_indextoname(idx, buf) == NULL) snprintf(buf, IFNAMSIZ, "if%u", idx); @@ -204,7 +252,9 @@ unsigned ll_name_to_index(const char *name) if (im) return im->index; - idx = if_nametoindex(name); + idx = ll_link_get(name, 0); + if (idx == 0) + idx = if_nametoindex(name); if (idx == 0) idx = ll_idx_a2n(name); return idx; -- 2.39.2