[RFC][PATCH 1/2] ip routing - split of ip_route_[in|out]put_slow

Einar Lueck
2004-09-13T10:38:14Z

We propose the following patch for splitting up
ip_route_[in|out]put_slow in inlined functions for two
reasons:
* improve overall comprehensibility (up to now these
functions are very large)
* allow for an easier application of a further patch
(please: refer to the subsequent patch for multipath
support with routing cache support)

Regards,
Einar

diff -ruN linux-2.6.8.1/net/ipv4/route.c
linux-2.6.8.1.split/net/ipv4/route.c
--- linux-2.6.8.1/net/ipv4/route.c 2004-09-09 20:47:02.000000000 +0200
+++ linux-2.6.8.1.split/net/ipv4/route.c 2004-09-09
20:56:35.000000000 +0200
@@ -104,6 +104,9 @@
#include <linux/sysctl.h>
#endif

+#define RT_FL_TOS(oldflp) \
+ ((u32)(oldflp->fl4_tos & (IPTOS_RT_MASK | RTO_ONLINK)))
+
#define IP_MAX_MTU 0xFFF0

#define RT_GC_TIMEOUT (300*HZ)
@@ -143,6 +146,7 @@
static void ipv4_link_failure(struct sk_buff *skb);
static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
static int rt_garbage_collect(void);
+static inline int compare_keys(struct flowi *fl1, struct flowi *fl2);

static struct dst_ops ipv4_dst_ops = {
@@ -1528,6 +1532,168 @@
return -EINVAL;
}

+
+static inline void ip_handle_martian_source(struct net_device *dev,
+ struct in_device *in_dev,
+ struct sk_buff *skb,
+ u32 daddr,
+ u32 saddr) {
+ RT_CACHE_STAT_INC(in_martian_src);
+#ifdef CONFIG_IP_ROUTE_VERBOSE
+ if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
+ /*
+ * RFC1812 recommendation, if source is martian,
+ * the only hint is MAC header.
+ */
+ printk(KERN_WARNING "martian source %u.%u.%u.%u from "
+ "%u.%u.%u.%u, on dev %s\n",
+ NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
+ if (dev->hard_header_len) {
+ int i;
+ unsigned char *p = skb->mac.raw;
+ printk(KERN_WARNING "ll header: ");
+ for (i = 0; i < dev->hard_header_len; i++, p++) {
+ printk("%02x", *p);
+ if (i < (dev->hard_header_len - 1))
+ printk(":");
+ }
+ printk("\n");
+ }
+ }
+#endif
+}
+
+static inline int __mkroute_input(struct sk_buff *skb,
+ struct fib_result* res,
+ struct in_device *in_dev,
+ u32 daddr, u32 saddr, u32 tos,
+ struct rtable **result)
+{
+
+ struct rtable *rth;
+ int err;
+ struct in_device *out_dev;
+ unsigned flags = 0;
+ u32 spec_dst, itag;
+
+ /* get a working reference to the output device */
+ out_dev = in_dev_get(FIB_RES_DEV(*res));
+ if (out_dev == NULL) {
+ if (net_ratelimit())
+ printk(KERN_CRIT "Bug in ip_route_input" \
+ "_slow(). Please, report\n");
+ return -EINVAL;
+ }
+
+
+ err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res),
+ in_dev->dev, &spec_dst, &itag);
+ if (err < 0) {
+ ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
+ saddr);
+
+ err = -EINVAL;
+ goto cleanup;
+ }
+
+ if (err)
+ flags |= RTCF_DIRECTSRC;
+
+ if (out_dev == in_dev && err && !(flags & (RTCF_NAT | RTCF_MASQ)) &&
+ (IN_DEV_SHARED_MEDIA(out_dev) ||
+ inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
+ flags |= RTCF_DOREDIRECT;
+
+ if (skb->protocol != htons(ETH_P_IP)) {
+ /* Not IP (i.e. ARP). Do not create route, if it is
+ * invalid for proxy arp. DNAT routes are always valid.
+ */
+ if (out_dev == in_dev && !(flags & RTCF_DNAT)) {
+ err = -EINVAL;
+ goto cleanup;
+ }
+ }
+
+
+ rth = dst_alloc(&ipv4_dst_ops);
+ if (!rth) {
+ err = -ENOBUFS;
+ goto cleanup;
+ }
+
+ rth->u.dst.flags= DST_HOST;
+ if (in_dev->cnf.no_policy)
+ rth->u.dst.flags |= DST_NOPOLICY;
+ if (in_dev->cnf.no_xfrm)
+ rth->u.dst.flags |= DST_NOXFRM;
+ rth->fl.fl4_dst = daddr;
+ rth->rt_dst = daddr;
+ rth->fl.fl4_tos = tos;
+#ifdef CONFIG_IP_ROUTE_FWMARK
+ rth->fl.fl4_fwmark= skb->nfmark;
+#endif
+ rth->fl.fl4_src = saddr;
+ rth->rt_src = saddr;
+ rth->rt_gateway = daddr;
+ rth->rt_iif =
+ rth->fl.iif = in_dev->dev->ifindex;
+ rth->u.dst.dev = (out_dev)->dev;
+ dev_hold(rth->u.dst.dev);
+ rth->idev = in_dev_get(rth->u.dst.dev);
+ rth->fl.oif = 0;
+ rth->rt_spec_dst= spec_dst;
+
+ rth->u.dst.input = ip_forward;
+ rth->u.dst.output = ip_output;
+
+ rt_set_nexthop(rth, res, itag);
+
+ rth->rt_flags = flags;
+
+ *result = rth;
+ err = 0;
+ cleanup:
+ /* release the working reference to the output device */
+ in_dev_put(out_dev);
+ return err;
+}
+
+static inline int ip_mkroute_input_def(struct sk_buff *skb,
+ struct fib_result* res,
+ const struct flowi *fl,
+ struct in_device *in_dev,
+ u32 daddr, u32 saddr, u32 tos)
+{
+ struct rtable* rth;
+ int err;
+ unsigned hash;
+
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+ if (res->fi->fib_nhs > 1 && fl->oif == 0)
+ fib_select_multipath(fl, res);
+#endif
+
+ /* create a routing cache entry */
+ err = __mkroute_input( skb, res, in_dev, daddr, saddr, tos, &rth );
+ if ( err )
+ return err;
+ atomic_set(&rth->u.dst.__refcnt, 1);
+
+ /* put it into the cache */
+ hash = rt_hash_code(daddr, saddr ^ (fl->iif << 5), tos);
+ return rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
+}
+
+static inline int ip_mkroute_input(struct sk_buff *skb,
+ struct fib_result* res,
+ const struct flowi *fl,
+ struct in_device *in_dev,
+ u32 daddr, u32 saddr, u32 tos)
+{
+ return ip_mkroute_input_def(skb, res, fl, in_dev, daddr, saddr, tos);
+}
+
+
/*
* NOTE. We drop all the packets that has local source
* addresses, because every properly looped back packet
@@ -1539,11 +1705,10 @@
*/

static int ip_route_input_slow(struct sk_buff *skb, u32 daddr, u32 saddr,
- u8 tos, struct net_device *dev)
+ u8 tos, struct net_device *dev)
{
struct fib_result res;
struct in_device *in_dev = in_dev_get(dev);
- struct in_device *out_dev = NULL;
struct flowi fl = { .nl_u = { .ip4_u =
{ .daddr = daddr,
.saddr = saddr,
@@ -1567,8 +1732,6 @@
if (!in_dev)
goto out;

- hash = rt_hash_code(daddr, saddr ^ (fl.iif << 5), tos);
-
/* Check for the most weird martians, which can be not detected
by fib_lookup.
*/
@@ -1621,79 +1784,14 @@
if (res.type != RTN_UNICAST)
goto martian_destination;

-#ifdef CONFIG_IP_ROUTE_MULTIPATH
- if (res.fi->fib_nhs > 1 && fl.oif == 0)
- fib_select_multipath(&fl, &res);
-#endif
- out_dev = in_dev_get(FIB_RES_DEV(res));
- if (out_dev == NULL) {
- if (net_ratelimit())
- printk(KERN_CRIT "Bug in ip_route_input_slow(). "
- "Please, report\n");
- goto e_inval;
- }
-
- err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(res), dev,
- &spec_dst, &itag);
- if (err < 0)
- goto martian_source;
-
- if (err)
- flags |= RTCF_DIRECTSRC;
-
- if (out_dev == in_dev && err && !(flags & (RTCF_NAT | RTCF_MASQ)) &&
- (IN_DEV_SHARED_MEDIA(out_dev) ||
- inet_addr_onlink(out_dev, saddr, FIB_RES_GW(res))))
- flags |= RTCF_DOREDIRECT;
-
- if (skb->protocol != htons(ETH_P_IP)) {
- /* Not IP (i.e. ARP). Do not create route, if it is
- * invalid for proxy arp. DNAT routes are always valid.
- */
- if (out_dev == in_dev && !(flags & RTCF_DNAT))
- goto e_inval;
- }
-
- rth = dst_alloc(&ipv4_dst_ops);
- if (!rth)
+ err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos);
+ if ( err == -ENOBUFS )
goto e_nobufs;
-
- atomic_set(&rth->u.dst.__refcnt, 1);
- rth->u.dst.flags= DST_HOST;
- if (in_dev->cnf.no_policy)
- rth->u.dst.flags |= DST_NOPOLICY;
- if (in_dev->cnf.no_xfrm)
- rth->u.dst.flags |= DST_NOXFRM;
- rth->fl.fl4_dst = daddr;
- rth->rt_dst = daddr;
- rth->fl.fl4_tos = tos;
-#ifdef CONFIG_IP_ROUTE_FWMARK
- rth->fl.fl4_fwmark= skb->nfmark;
-#endif
- rth->fl.fl4_src = saddr;
- rth->rt_src = saddr;
- rth->rt_gateway = daddr;
- rth->rt_iif =
- rth->fl.iif = dev->ifindex;
- rth->u.dst.dev = out_dev->dev;
- dev_hold(rth->u.dst.dev);
- rth->idev = in_dev_get(rth->u.dst.dev);
- rth->fl.oif = 0;
- rth->rt_spec_dst= spec_dst;
-
- rth->u.dst.input = ip_forward;
- rth->u.dst.output = ip_output;
-
- rt_set_nexthop(rth, &res, itag);
-
- rth->rt_flags = flags;
-
-intern:
- err = rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
+ if ( err == -EINVAL )
+ goto e_inval;
+
done:
in_dev_put(in_dev);
- if (out_dev)
- in_dev_put(out_dev);
if (free_res)
fib_res_put(&res);
out: return err;
@@ -1753,7 +1851,9 @@
rth->rt_flags &= ~RTCF_LOCAL;
}
rth->rt_type = res.type;
- goto intern;
+ hash = rt_hash_code(daddr, saddr ^ (fl.iif << 5), tos);
+ err = rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
+ goto done;

no_route:
RT_CACHE_STAT_INC(in_no_route);
@@ -1875,13 +1975,166 @@
return ip_route_input_slow(skb, daddr, saddr, tos, dev);
}

+static inline int __mkroute_output(struct rtable **result,
+ struct fib_result* res,
+ const struct flowi *fl,
+ const struct flowi *oldflp,
+ struct net_device *dev_out,
+ unsigned flags)
+{
+ struct rtable *rth;
+ struct in_device *in_dev;
+ u32 tos = RT_FL_TOS(oldflp);
+ int err = 0;
+
+ if (LOOPBACK(fl->fl4_src) && !(dev_out->flags&IFF_LOOPBACK))
+ return -EINVAL;
+
+ if (fl->fl4_dst == 0xFFFFFFFF)
+ res->type = RTN_BROADCAST;
+ else if (MULTICAST(fl->fl4_dst))
+ res->type = RTN_MULTICAST;
+ else if (BADCLASS(fl->fl4_dst) || ZERONET(fl->fl4_dst))
+ return -EINVAL;
+
+ if (dev_out->flags & IFF_LOOPBACK)
+ flags |= RTCF_LOCAL;
+
+ /* get work reference to inet device */
+ in_dev = in_dev_get(dev_out);
+ if (!in_dev)
+ return -EINVAL;
+
+ if (res->type == RTN_BROADCAST) {
+ flags |= RTCF_BROADCAST | RTCF_LOCAL;
+ if (res->fi) {
+ fib_info_put(res->fi);
+ res->fi = NULL;
+ }
+ } else if (res->type == RTN_MULTICAST) {
+ flags |= RTCF_MULTICAST|RTCF_LOCAL;
+ if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
+ oldflp->proto))
+ flags &= ~RTCF_LOCAL;
+ /* If multicast route do not exist use
+ default one, but do not gateway in this case.
+ Yes, it is hack.
+ */
+ if (res->fi && res->prefixlen < 4) {
+ fib_info_put(res->fi);
+ res->fi = NULL;
+ }
+ }
+
+
+ rth = dst_alloc(&ipv4_dst_ops);
+ if (!rth) {
+ err = -ENOBUFS;
+ goto cleanup;
+ }
+
+ rth->u.dst.flags= DST_HOST;
+ if (in_dev->cnf.no_xfrm)
+ rth->u.dst.flags |= DST_NOXFRM;
+ if (in_dev->cnf.no_policy)
+ rth->u.dst.flags |= DST_NOPOLICY;
+
+ rth->fl.fl4_dst = oldflp->fl4_dst;
+ rth->fl.fl4_tos = tos;
+ rth->fl.fl4_src = oldflp->fl4_src;
+ rth->fl.oif = oldflp->oif;
+#ifdef CONFIG_IP_ROUTE_FWMARK
+ rth->fl.fl4_fwmark= oldflp->fl4_fwmark;
+#endif
+ rth->rt_dst = fl->fl4_dst;
+ rth->rt_src = fl->fl4_src;
+ rth->rt_iif = oldflp->oif ? : dev_out->ifindex;
+ /* get references to the devices that are to be hold by the routing
+ cache entry */
+ rth->u.dst.dev = dev_out;
+ dev_hold(dev_out);
+ rth->idev = in_dev_get(dev_out);
+ rth->rt_gateway = fl->fl4_dst;
+ rth->rt_spec_dst= fl->fl4_src;
+
+ rth->u.dst.output=ip_output;
+
+ RT_CACHE_STAT_INC(out_slow_tot);
+
+ if (flags & RTCF_LOCAL) {
+ rth->u.dst.input = ip_local_deliver;
+ rth->rt_spec_dst = fl->fl4_dst;
+ }
+ if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
+ rth->rt_spec_dst = fl->fl4_src;
+ if (flags & RTCF_LOCAL &&
+ !(dev_out->flags & IFF_LOOPBACK)) {
+ rth->u.dst.output = ip_mc_output;
+ RT_CACHE_STAT_INC(out_slow_mc);
+ }
+#ifdef CONFIG_IP_MROUTE
+ if (res->type == RTN_MULTICAST) {
+ if (IN_DEV_MFORWARD(in_dev) &&
+ !LOCAL_MCAST(oldflp->fl4_dst)) {
+ rth->u.dst.input = ip_mr_input;
+ rth->u.dst.output = ip_mc_output;
+ }
+ }
+#endif
+ }
+
+ rt_set_nexthop(rth, res, 0);
+
+ rth->rt_flags = flags;
+
+ *result = rth;
+ cleanup:
+ /* release work reference to inet device */
+ in_dev_put(in_dev);
+
+ return err;
+}
+
+static inline int ip_mkroute_output_def(struct rtable **rp,
+ struct fib_result* res,
+ const struct flowi *fl,
+ const struct flowi *oldflp,
+ struct net_device *dev_out,
+ unsigned flags)
+{
+ struct rtable *rth;
+ int err = __mkroute_output(&rth, res, fl, oldflp, dev_out, flags);
+ unsigned hash;
+ if ( err == 0 ) {
+ u32 tos = RT_FL_TOS(oldflp);
+
+ atomic_set(&rth->u.dst.__refcnt, 1);
+
+ hash = rt_hash_code(oldflp->fl4_dst,
+ oldflp->fl4_src ^ (oldflp->oif << 5), tos);
+ err = rt_intern_hash(hash, rth, rp);
+ }
+
+ return err;
+}
+
+static inline int ip_mkroute_output(struct rtable** rp,
+ struct fib_result* res,
+ const struct flowi *fl,
+ const struct flowi *oldflp,
+ struct net_device *dev_out,
+ unsigned flags)
+{
+ return ip_mkroute_output_def(rp, res, fl, oldflp, dev_out, flags);
+}
+
/*
* Major route resolver routine.
*/

static int ip_route_output_slow(struct rtable **rp, const struct flowi
*oldflp)
{
- u32 tos = oldflp->fl4_tos & (IPTOS_RT_MASK | RTO_ONLINK);
+ u32 tos = RT_FL_TOS(oldflp);
struct flowi fl = { .nl_u = { .ip4_u =
{ .daddr = oldflp->fl4_dst,
.saddr = oldflp->fl4_src,
@@ -1897,10 +2150,7 @@
.oif = oldflp->oif };
struct fib_result res;
unsigned flags = 0;
- struct rtable *rth;
struct net_device *dev_out = NULL;
- struct in_device *in_dev = NULL;
- unsigned hash;
int free_res = 0;
int err;

@@ -2060,116 +2310,13 @@
fl.oif = dev_out->ifindex;

make_route:
- if (LOOPBACK(fl.fl4_src) && !(dev_out->flags&IFF_LOOPBACK))
- goto e_inval;
-
- if (fl.fl4_dst == 0xFFFFFFFF)
- res.type = RTN_BROADCAST;
- else if (MULTICAST(fl.fl4_dst))
- res.type = RTN_MULTICAST;
- else if (BADCLASS(fl.fl4_dst) || ZERONET(fl.fl4_dst))
- goto e_inval;
-
- if (dev_out->flags & IFF_LOOPBACK)
- flags |= RTCF_LOCAL;
-
- in_dev = in_dev_get(dev_out);
- if (!in_dev)
- goto e_inval;
-
- if (res.type == RTN_BROADCAST) {
- flags |= RTCF_BROADCAST | RTCF_LOCAL;
- if (res.fi) {
- fib_info_put(res.fi);
- res.fi = NULL;
- }
- } else if (res.type == RTN_MULTICAST) {
- flags |= RTCF_MULTICAST|RTCF_LOCAL;
- if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
oldflp->proto))
- flags &= ~RTCF_LOCAL;
- /* If multicast route do not exist use
- default one, but do not gateway in this case.
- Yes, it is hack.
- */
- if (res.fi && res.prefixlen < 4) {
- fib_info_put(res.fi);
- res.fi = NULL;
- }
- }
-
- rth = dst_alloc(&ipv4_dst_ops);
- if (!rth)
- goto e_nobufs;
+ err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags);

- atomic_set(&rth->u.dst.__refcnt, 1);
- rth->u.dst.flags= DST_HOST;
- if (in_dev->cnf.no_xfrm)
- rth->u.dst.flags |= DST_NOXFRM;
- if (in_dev->cnf.no_policy)
- rth->u.dst.flags |= DST_NOPOLICY;
- rth->fl.fl4_dst = oldflp->fl4_dst;
- rth->fl.fl4_tos = tos;
- rth->fl.fl4_src = oldflp->fl4_src;
- rth->fl.oif = oldflp->oif;
-#ifdef CONFIG_IP_ROUTE_FWMARK
- rth->fl.fl4_fwmark= oldflp->fl4_fwmark;
-#endif
- rth->rt_dst = fl.fl4_dst;
- rth->rt_src = fl.fl4_src;
- rth->rt_iif = oldflp->oif ? : dev_out->ifindex;
- rth->u.dst.dev = dev_out;
- dev_hold(dev_out);
- rth->idev = in_dev_get(dev_out);
- rth->rt_gateway = fl.fl4_dst;
- rth->rt_spec_dst= fl.fl4_src;
-
- rth->u.dst.output=ip_output;
-
- RT_CACHE_STAT_INC(out_slow_tot);
-
- if (flags & RTCF_LOCAL) {
- rth->u.dst.input = ip_local_deliver;
- rth->rt_spec_dst = fl.fl4_dst;
- }
- if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
- rth->rt_spec_dst = fl.fl4_src;
- if (flags & RTCF_LOCAL && !(dev_out->flags & IFF_LOOPBACK)) {
- rth->u.dst.output = ip_mc_output;
- RT_CACHE_STAT_INC(out_slow_mc);
- }
-#ifdef CONFIG_IP_MROUTE
- if (res.type == RTN_MULTICAST) {
- if (IN_DEV_MFORWARD(in_dev) &&
- !LOCAL_MCAST(oldflp->fl4_dst)) {
- rth->u.dst.input = ip_mr_input;
- rth->u.dst.output = ip_mc_output;
- }
- }
-#endif
- }
-
- rt_set_nexthop(rth, &res, 0);
-
-
- rth->rt_flags = flags;
-
- hash = rt_hash_code(oldflp->fl4_dst, oldflp->fl4_src ^ (oldflp->oif
<< 5), tos);
- err = rt_intern_hash(hash, rth, rp);
-done:
if (free_res)
fib_res_put(&res);
if (dev_out)
dev_put(dev_out);
- if (in_dev)
- in_dev_put(in_dev);
out: return err;
-
-e_inval:
- err = -EINVAL;
- goto done;
-e_nobufs:
- err = -ENOBUFS;
- goto done;
}

int __ip_route_output_key(struct rtable **rp, const struct flowi *flp)