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Optimize IP fastforwarding some more:

Browse Source 
o New function ip_findroute() to reduce code duplication for the
  route lookup cases. (luigi)

o Store ip_len in host byte order on the stack instead of using
  it via indirection from the mbuf.  This allows to defer the host
  byte conversion to a later point and makes a quicker fallback to
  normal ip_input() processing. (luigi)

o Check if route is dampned with RTF_REJECT flag and drop packet
  already here when ARP is unable to resolve destination address.
  An ICMP unreachable is sent to inform the sender.

o Check if interface output queue is full and drop packet already
  here.  No ICMP notification is sent because signalling source quench
  is depreciated.

o Check if media_state is down (used for ethernet type interfaces)
  and drop the packet already here.  An ICMP unreachable is sent to
  inform the sender.

o Do not account sent packets to the interface address counters.  They
  are only for packets with that 'ia' as source address.

o Update and clarify some comments.

Submitted by:	luigi (most of it)
This commit is contained in:
Andre Oppermann 2004-05-03 13:52:47 +00:00
parent 127d7b2d2d
commit 06bb56f43c
1 changed files with 114 additions and 95 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

209
sys/netinet/ip_fastfwd.c
View File

@ -117,6 +117,42 @@ static int ipfastforward_active = 0;
SYSCTL_INT(_net_inet_ip, OID_AUTO, fastforwarding, CTLFLAG_RW,
&ipfastforward_active, 0, "Enable fast IP forwarding");
static struct sockaddr_in *
ip_findroute(struct route *ro, in_addr_t dest, struct mbuf *m)
{
struct sockaddr_in *dst;
struct rtentry *rt;
/*
* Find route to destination.
*/
bzero(ro, sizeof(*ro));
dst = (struct sockaddr_in *)&ro->ro_dst;
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr.s_addr = dest;
rtalloc_ign(ro, RTF_CLONING);
/*
* Route there and interface still up?
*/
rt = ro->ro_rt;
if (rt && (rt->rt_flags & RTF_UP) &&
(rt->rt_ifp->if_flags & IFF_UP) &&
(rt->rt_ifp->if_flags & IFF_RUNNING)) {
if (rt->rt_flags & RTF_GATEWAY)
dst = (struct sockaddr_in *)rt->rt_gateway;
} else {
ipstat.ips_noroute++;
ipstat.ips_cantforward++;
if (rt)
RTFREE(rt);
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL);
return NULL;
}
return dst;
}
/*
* Try to forward a packet based on the destination address.
* This is a fast path optimized for the plain forwarding case.
@ -137,10 +173,10 @@ ip_fastforward(struct mbuf *m)
struct sockaddr_in *dst = NULL;
struct in_ifaddr *ia = NULL;
struct ifaddr *ifa = NULL;
struct ifnet *ifp = NULL;
struct ifnet *ifp;
struct ip_fw_args args;
in_addr_t odest, dest;
u_short sum;
u_short sum, ip_len;
int error = 0;
int hlen, ipfw, mtu;
@ -153,6 +189,8 @@ ip_fastforward(struct mbuf *m)
M_ASSERTVALID(m);
M_ASSERTPKTHDR(m);
ro.ro_rt = NULL;
/*
* Step 1: check for packet drop conditions (and sanity checks)
*/
@ -217,16 +255,12 @@ ip_fastforward(struct mbuf *m)
}
m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
/*
* Convert to host representation
*/
ip->ip_len = ntohs(ip->ip_len);
ip->ip_off = ntohs(ip->ip_off);
ip_len = ntohs(ip->ip_len);
/*
* Is IP length longer than packet we have got?
*/
if (m->m_pkthdr.len < ip->ip_len) {
if (m->m_pkthdr.len < ip_len) {
ipstat.ips_tooshort++;
goto drop;
}
@ -234,12 +268,12 @@ ip_fastforward(struct mbuf *m)
/*
* Is packet longer than IP header tells us? If yes, truncate packet.
*/
if (m->m_pkthdr.len > ip->ip_len) {
if (m->m_pkthdr.len > ip_len) {
if (m->m_len == m->m_pkthdr.len) {
m->m_len = ip->ip_len;
m->m_pkthdr.len = ip->ip_len;
m->m_len = ip_len;
m->m_pkthdr.len = ip_len;
} else
m_adj(m, ip->ip_len - m->m_pkthdr.len);
m_adj(m, ip_len - m->m_pkthdr.len);
}
/*
@ -258,8 +292,16 @@ ip_fastforward(struct mbuf *m)
/*
* Only IP packets without options
*/
if (ip->ip_hl != (sizeof(struct ip) >> 2))
goto fallback;
if (ip->ip_hl != (sizeof(struct ip) >> 2)) {
if (ip_doopts == 1)
return 0;
else if (ip_doopts == 2) {
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_FILTER_PROHIB,
0, NULL);
return 1;
}
/* else ignore IP options and continue */
}
/*
* Only unicast IP, not from loopback, no L2 or IP broadcast,
@ -277,14 +319,14 @@ ip_fastforward(struct mbuf *m)
IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
ip->ip_dst.s_addr == INADDR_ANY )
goto fallback;
return 0;
/*
* Is it for a local address on this host?
*/
LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr)
goto fallback;
return 0;
}
/*
@ -296,16 +338,10 @@ ip_fastforward(struct mbuf *m)
continue;
ia = ifatoia(ifa);
if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr)
goto fallback;
return 0;
if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
ip->ip_dst.s_addr)
goto fallback;
continue;
fallback:
/* return packet back to netisr for slow processing */
ip->ip_len = htons(ip->ip_len);
ip->ip_off = htons(ip->ip_off);
return 0;
return 0;
}
}
ipstat.ips_total++;
@ -314,6 +350,12 @@ ip_fastforward(struct mbuf *m)
* Step 3: incoming packet firewall processing
*/
/*
* Convert to host representation
*/
ip->ip_len = ntohs(ip->ip_len);
ip->ip_off = ntohs(ip->ip_off);
odest = dest = ip->ip_dst.s_addr;
#ifdef PFIL_HOOKS
/*
@ -462,31 +504,9 @@ ip_fastforward(struct mbuf *m)
/*
* Find route to destination.
*/
bzero(&ro, sizeof(ro));
dst = (struct sockaddr_in *)&ro.ro_dst;
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr.s_addr = dest;
rtalloc_ign(&ro, RTF_CLONING);
/*
* Route there and interface still up?
*/
if (ro.ro_rt &&
(ro.ro_rt->rt_flags & RTF_UP) &&
(ro.ro_rt->rt_ifp->if_flags & IFF_UP)) {
ia = ifatoia(ro.ro_rt->rt_ifa);
ifp = ro.ro_rt->rt_ifp;
if (ro.ro_rt->rt_flags & RTF_GATEWAY)
dst = (struct sockaddr_in *)ro.ro_rt->rt_gateway;
} else {
ipstat.ips_noroute++;
ipstat.ips_cantforward++;
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL);
if (ro.ro_rt)
RTFREE(ro.ro_rt);
return 1;
}
if ((dst = ip_findroute(&ro, dest, m)) == NULL)
return 1; /* icmp unreach already sent */
ifp = ro.ro_rt->rt_ifp;
/*
* Step 5: outgoing firewall packet processing
@ -497,8 +517,7 @@ ip_fastforward(struct mbuf *m)
* Run through list of hooks for output packets.
*/
if (pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT) || m == NULL) {
RTFREE(ro.ro_rt);
return 1;
goto consumed;
}
M_ASSERTVALID(m);
@ -518,10 +537,9 @@ ip_fastforward(struct mbuf *m)
M_ASSERTVALID(m);
M_ASSERTPKTHDR(m);
if ((ipfw & IP_FW_PORT_DENY_FLAG) || m == NULL) {
RTFREE(ro.ro_rt);
if ((ipfw & IP_FW_PORT_DENY_FLAG) || m == NULL)
goto drop;
}
if (DUMMYNET_LOADED && (ipfw & IP_FW_PORT_DYNT_FLAG) != 0) {
/*
* XXX note: if the ifp or rt entry are deleted
@ -531,8 +549,7 @@ ip_fastforward(struct mbuf *m)
args.dst = dst;
ip_dn_io_ptr(m, ipfw & 0xffff, DN_TO_IP_OUT, &args);
RTFREE(ro.ro_rt);
return 1;
goto consumed;
}
#ifdef IPDIVERT
if (ipfw != 0 && (ipfw & IP_FW_PORT_DYNT_FLAG) == 0) {
@ -573,8 +590,7 @@ ip_fastforward(struct mbuf *m)
*/
m = clone;
if ((ipfw & IP_FW_PORT_TEE_FLAG) == 0) {
RTFREE(ro.ro_rt);
return 1;
goto consumed;
}
/* Continue if it was tee */
goto passout;
@ -609,8 +625,6 @@ ip_fastforward(struct mbuf *m)
sizeof(struct sockaddr_in *),
M_NOWAIT);
if (mtag == NULL) {
if (ro.ro_rt)
RTFREE(ro.ro_rt);
goto drop;
}
*(struct sockaddr_in **)(mtag+1) =
@ -639,37 +653,42 @@ ip_fastforward(struct mbuf *m)
* Redo route lookup with new destination address
*/
RTFREE(ro.ro_rt);
bzero(&ro, sizeof(ro));
dst = (struct sockaddr_in *)&ro.ro_dst;
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr.s_addr = dest;
rtalloc_ign(&ro, RTF_CLONING);
/*
* Route there and interface still up?
*/
if (ro.ro_rt &&
(ro.ro_rt->rt_flags & RTF_UP) &&
(ro.ro_rt->rt_ifp->if_flags & IFF_UP)) {
ia = ifatoia(ro.ro_rt->rt_ifa);
ifp = ro.ro_rt->rt_ifp;
if (ro.ro_rt->rt_flags & RTF_GATEWAY)
dst = (struct sockaddr_in *)ro.ro_rt->rt_gateway;
} else {
ipstat.ips_noroute++;
ipstat.ips_cantforward++;
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL);
if (ro.ro_rt)
RTFREE(ro.ro_rt);
return 1;
}
if ((dst = ip_findroute(&ro, dest, m)) == NULL)
return 1; /* icmp unreach already sent */
ifp = ro.ro_rt->rt_ifp;
}
/*
* Step 6: send off the packet
*/
/*
* Check if route is dampned (when ARP is unable to resolve)
*/
if ((ro.ro_rt->rt_flags & RTF_REJECT) &&
ro.ro_rt->rt_rmx.rmx_expire >= time_second) {
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL);
goto consumed;
}
/*
* Check if there is enough space in the interface queue
*/
if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
ifp->if_snd.ifq_maxlen) {
ipstat.ips_odropped++;
/* would send source quench here but that is depreciated */
goto drop;
}
/*
* Check if media link state of interface is not down
*/
if (ifp->if_link_state == LINK_STATE_DOWN) {
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL);
goto consumed;
}
/*
* Check if packet fits MTU or if hardware will fragement for us
*/
@ -690,29 +709,26 @@ ip_fastforward(struct mbuf *m)
*/
error = (*ifp->if_output)(ifp, m,
(struct sockaddr *)dst, ro.ro_rt);
if (ia) {
ia->ia_ifa.if_opackets++;
ia->ia_ifa.if_obytes += m->m_pkthdr.len;
}
} else {
/*
* Handle EMSGSIZE with icmp reply
* needfrag for TCP MTU discovery
* Handle EMSGSIZE with icmp reply needfrag for TCP MTU discovery
*/
if (ip->ip_off & IP_DF) {
ipstat.ips_cantfrag++;
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG,
0, ifp);
ipstat.ips_cantfrag++;
RTFREE(ro.ro_rt);
return 1;
goto consumed;
} else {
/*
* We have to fragement the packet
*/
m->m_pkthdr.csum_flags |= CSUM_IP;
/*
* ip_fragment expects ip_len and ip_off in host byte
* order but returns all packets in network byte order
*/
if (ip_fragment(ip, &m, mtu, ifp->if_hwassist,
(~ifp->if_hwassist & CSUM_DELAY_IP))) {
RTFREE(ro.ro_rt);
goto drop;
}
KASSERT(m != NULL, ("null mbuf and no error"));
@ -748,10 +764,13 @@ ip_fastforward(struct mbuf *m)
ipstat.ips_forward++;
ipstat.ips_fastforward++;
}
consumed:
RTFREE(ro.ro_rt);
return 1;
drop:
if (m)
m_freem(m);
if (ro.ro_rt)
RTFREE(ro.ro_rt);
return 1;
}