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route cache return hit or miss
On Fri, Feb 09, 2024 at 11:45:12AM +0100, Alexander Bluhm wrote:
> On Fri, Feb 09, 2024 at 08:39:32AM +0100, Claudio Jeker wrote:
> > On Thu, Feb 08, 2024 at 11:15:40PM +0100, Alexander Bluhm wrote:
> > > Hi,
> > >
> > > The route_cache() function can easily return whether it was a cache
> > > hit or miss. Then the logic to perform a route lookup gets a bit
> > > simpler. Some more complicated if (ro->ro_rt == NULL) checks still
> > > exist elsewhere.
> > >
> > > Also use route cache in in_pcbselsrc() instead of filling struct
> > > route manually.
> > >
> > > ok?
> >
> > Why return ESRCH instead of simply -1?
>
> I don't like functions that return 0, 1, or -1 in general. This
> way you may reach the OpenSSL API design.
But route_cache() is a simple boolean function. There is no complexity in
it. It eiter was a cache hit or it wasn't.
> Functions that allocate should return pointer or NULL.
> Boolean questions like rtisvalid() return 0 or 1.
I prefer 0 and -1 for boolean returns.
> All others either succeed or fail. Failure should be expressed by
> an errno. Lookups usually return ESRCH if an object is not there.
> Returning error number makes is more readble what is expected and
> what happens in the other cases.
In any case this is just a bikeshed issue.
OK claudio@ on the diff.
> bluhm
>
> > Apart from that I like this a lot.
> >
> > > Index: net/route.c
> > > ===================================================================
> > > RCS file: /data/mirror/openbsd/cvs/src/sys/net/route.c,v
> > > diff -u -p -r1.430 route.c
> > > --- net/route.c 7 Feb 2024 23:52:20 -0000 1.430
> > > +++ net/route.c 8 Feb 2024 14:43:01 -0000
> > > @@ -201,7 +201,7 @@ route_init(void)
> > > #endif
> > > }
> > >
> > > -void
> > > +int
> > > route_cache(struct route *ro, struct in_addr addr, u_int rtableid)
> > > {
> > > u_long gen;
> > > @@ -215,7 +215,7 @@ route_cache(struct route *ro, struct in_
> > > ro->ro_dst.sa_family == AF_INET &&
> > > satosin(&ro->ro_dst)->sin_addr.s_addr == addr.s_addr) {
> > > ipstat_inc(ips_rtcachehit);
> > > - return;
> > > + return (0);
> > > }
> > >
> > > ipstat_inc(ips_rtcachemiss);
> > > @@ -228,10 +228,12 @@ route_cache(struct route *ro, struct in_
> > > satosin(&ro->ro_dst)->sin_family = AF_INET;
> > > satosin(&ro->ro_dst)->sin_len = sizeof(struct sockaddr_in);
> > > satosin(&ro->ro_dst)->sin_addr = addr;
> > > +
> > > + return (ESRCH);
> > > }
> > >
> > > #ifdef INET6
> > > -void
> > > +int
> > > route6_cache(struct route_in6 *ro, const struct in6_addr *addr,
> > > u_int rtableid)
> > > {
> > > @@ -246,7 +248,7 @@ route6_cache(struct route_in6 *ro, const
> > > ro->ro_dst.sin6_family == AF_INET6 &&
> > > IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, addr)) {
> > > ip6stat_inc(ip6s_rtcachehit);
> > > - return;
> > > + return (0);
> > > }
> > >
> > > ip6stat_inc(ip6s_rtcachemiss);
> > > @@ -259,6 +261,8 @@ route6_cache(struct route_in6 *ro, const
> > > ro->ro_dst.sin6_family = AF_INET6;
> > > ro->ro_dst.sin6_len = sizeof(struct sockaddr_in6);
> > > ro->ro_dst.sin6_addr = *addr;
> > > +
> > > + return (ESRCH);
> > > }
> > > #endif
> > >
> > > Index: netinet/in.h
> > > ===================================================================
> > > RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/in.h,v
> > > diff -u -p -r1.146 in.h
> > > --- netinet/in.h 5 Feb 2024 12:52:11 -0000 1.146
> > > +++ netinet/in.h 8 Feb 2024 14:37:42 -0000
> > > @@ -789,7 +789,7 @@ void in_len2mask(struct in_addr *, in
> > > int in_nam2sin(const struct mbuf *, struct sockaddr_in **);
> > > int in_sa2sin(struct sockaddr *, struct sockaddr_in **);
> > >
> > > -void route_cache(struct route *, struct in_addr, u_int);
> > > +int route_cache(struct route *, struct in_addr, u_int);
> > >
> > > char *inet_ntoa(struct in_addr);
> > > int inet_nat64(int, const void *, void *, const void *, u_int8_t);
> > > Index: netinet/in_pcb.c
> > > ===================================================================
> > > RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/in_pcb.c,v
> > > diff -u -p -r1.290 in_pcb.c
> > > --- netinet/in_pcb.c 7 Feb 2024 23:40:40 -0000 1.290
> > > +++ netinet/in_pcb.c 8 Feb 2024 14:44:49 -0000
> > > @@ -918,8 +918,7 @@ in_pcbrtentry(struct inpcb *inp)
> > >
> > > if (inp->inp_faddr.s_addr == INADDR_ANY)
> > > return (NULL);
> > > - route_cache(ro, inp->inp_faddr, inp->inp_rtableid);
> > > - if (ro->ro_rt == NULL) {
> > > + if (route_cache(ro, inp->inp_faddr, inp->inp_rtableid)) {
> > > ro->ro_rt = rtalloc_mpath(&ro->ro_dst,
> > > &inp->inp_laddr.s_addr, ro->ro_tableid);
> > > }
> > > @@ -941,8 +940,6 @@ in_pcbselsrc(struct in_addr *insrc, stru
> > > const struct in_addr *laddr = &inp->inp_laddr;
> > > u_int rtableid = inp->inp_rtableid;
> > > struct sockaddr *ip4_source = NULL;
> > > -
> > > - struct sockaddr_in *sin2;
> > > struct in_ifaddr *ia = NULL;
> > >
> > > /*
> > > @@ -984,25 +981,9 @@ in_pcbselsrc(struct in_addr *insrc, stru
> > > * If route is known or can be allocated now,
> > > * our src addr is taken from the i/f, else punt.
> > > */
> > > - if (!rtisvalid(ro->ro_rt) || (ro->ro_tableid != rtableid) ||
> > > - (satosin(&ro->ro_dst)->sin_addr.s_addr != sin->sin_addr.s_addr)) {
> > > - rtfree(ro->ro_rt);
> > > - ro->ro_rt = NULL;
> > > - }
> > > - if (ro->ro_rt == NULL) {
> > > + if (route_cache(ro, sin->sin_addr, rtableid)) {
> > > /* No route yet, so try to acquire one */
> > > - ro->ro_dst.sa_family = AF_INET;
> > > - ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
> > > - satosin(&ro->ro_dst)->sin_addr = sin->sin_addr;
> > > - ro->ro_tableid = rtableid;
> > > ro->ro_rt = rtalloc_mpath(&ro->ro_dst, NULL, ro->ro_tableid);
> > > -
> > > - /*
> > > - * It is important to zero out the rest of the
> > > - * struct sockaddr_in when mixing v6 & v4!
> > > - */
> > > - sin2 = satosin(&ro->ro_dst);
> > > - memset(sin2->sin_zero, 0, sizeof(sin2->sin_zero));
> > > }
> > >
> > > /*
> > > Index: netinet6/in6.h
> > > ===================================================================
> > > RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/in6.h,v
> > > diff -u -p -r1.114 in6.h
> > > --- netinet6/in6.h 7 Feb 2024 23:40:40 -0000 1.114
> > > +++ netinet6/in6.h 8 Feb 2024 14:38:13 -0000
> > > @@ -428,7 +428,7 @@ int in6_mask2len(struct in6_addr *, u_ch
> > > int in6_nam2sin6(const struct mbuf *, struct sockaddr_in6 **);
> > > int in6_sa2sin6(struct sockaddr *, struct sockaddr_in6 **);
> > >
> > > -void route6_cache(struct route_in6 *, const struct in6_addr *, u_int);
> > > +int route6_cache(struct route_in6 *, const struct in6_addr *, u_int);
> > >
> > > struct ip6_pktopts;
> > > struct ip6_moptions;
> > > Index: netinet6/in6_pcb.c
> > > ===================================================================
> > > RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/in6_pcb.c,v
> > > diff -u -p -r1.135 in6_pcb.c
> > > --- netinet6/in6_pcb.c 7 Feb 2024 23:40:40 -0000 1.135
> > > +++ netinet6/in6_pcb.c 8 Feb 2024 14:47:09 -0000
> > > @@ -568,8 +568,7 @@ in6_pcbrtentry(struct inpcb *inp)
> > >
> > > if (IN6_IS_ADDR_UNSPECIFIED(&inp->inp_faddr6))
> > > return (NULL);
> > > - route6_cache(ro, &inp->inp_faddr6, inp->inp_rtableid);
> > > - if (ro->ro_rt == NULL) {
> > > + if (route6_cache(ro, &inp->inp_faddr6, inp->inp_rtableid)) {
> > > ro->ro_rt = rtalloc_mpath(sin6tosa(&ro->ro_dst),
> > > &inp->inp_laddr6.s6_addr32[0], ro->ro_tableid);
> > > }
> > > Index: netinet6/in6_src.c
> > > ===================================================================
> > > RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/in6_src.c,v
> > > diff -u -p -r1.92 in6_src.c
> > > --- netinet6/in6_src.c 7 Feb 2024 23:40:40 -0000 1.92
> > > +++ netinet6/in6_src.c 8 Feb 2024 14:48:05 -0000
> > > @@ -179,8 +179,7 @@ in6_pcbselsrc(const struct in6_addr **in
> > > * If route is known or can be allocated now,
> > > * our src addr is taken from the i/f, else punt.
> > > */
> > > - route6_cache(ro, dst, rtableid);
> > > - if (ro->ro_rt == NULL) {
> > > + if (route6_cache(ro, dst, rtableid)) {
> > > ro->ro_rt = rtalloc(sin6tosa(&ro->ro_dst),
> > > RT_RESOLVE, ro->ro_tableid);
> > > }
> > > @@ -306,8 +305,7 @@ in6_selectroute(const struct in6_addr *d
> > > * a new one.
> > > */
> > > if (ro) {
> > > - route6_cache(ro, dst, rtableid);
> > > - if (ro->ro_rt == NULL) {
> > > + if (route6_cache(ro, dst, rtableid)) {
> > > /* No route yet, so try to acquire one */
> > > ro->ro_rt = rtalloc_mpath(sin6tosa(&ro->ro_dst),
> > > NULL, ro->ro_tableid);
> > >
> >
> > --
> > :wq Claudio
>
--
:wq Claudio
route cache return hit or miss