d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Convert ip6_forward() to the new routing KPI.

Browse Source 
Update ip6_forward() internals to use deembedded IPv6 addresses
 to simplify calls to the new KPI and prepare for the future
 scope-embedding cleanup.

Add in6_get_unicast_scopeid() and in6_set_unicast_scopeid() scopeid
 operation functions tailored for unicast processing.

Reviewed by:	ae
Differential Revision:	https://reviews.freebsd.org/D24334
This commit is contained in:
Alexander V. Chernikov 2020-04-15 12:56:05 +00:00
parent 4afeb43d98
commit 53a4886d5d
3 changed files with 101 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

135
sys/netinet6/ip6_forward.c
View File

@ -56,6 +56,7 @@ __FBSDID("$FreeBSD$");
#include <net/if_var.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/route/nhop.h>
#include <net/pfil.h>
#include <netinet/in.h>
@ -65,6 +66,7 @@ __FBSDID("$FreeBSD$");
#include <netinet/ip_var.h>
#include <netinet6/in6_var.h>
#include <netinet/ip6.h>
#include <netinet6/in6_fib.h>
#include <netinet6/ip6_var.h>
#include <netinet6/scope6_var.h>
#include <netinet/icmp6.h>
@ -90,14 +92,13 @@ void
ip6_forward(struct mbuf *m, int srcrt)
{
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
struct sockaddr_in6 *dst = NULL;
struct rtentry *rt = NULL;
struct route_in6 rin6;
struct sockaddr_in6 dst;
struct nhop_object *nh = NULL;
int error, type = 0, code = 0;
struct mbuf *mcopy = NULL;
struct ifnet *origifp; /* maybe unnecessary */
u_int32_t inzone, outzone;
struct in6_addr src_in6, dst_in6, odst;
struct in6_addr odst;
struct m_tag *fwd_tag;
char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
@ -165,18 +166,27 @@ ip6_forward(struct mbuf *m, int srcrt)
/* No IPsec processing required */
}
#endif
/*
* ip6_forward() operates with IPv6 addresses with deembedded scope.
*
* There are 3 sources of IPv6 destination address:
*
* 1) ip6_input(), where ip6_dst contains deembedded address.
* In order to deal with forwarding of link-local packets,
* calculate the scope based on input interface (RFC 4007, clause 9).
* 2) packet filters changing ip6_dst directly. It would embed scope
* for LL addresses, so in6_localip() performs properly.
* 3) packet filters attaching PACKET_TAG_IPFORWARD would embed
* scope for the nexthop.
*/
bzero(&dst, sizeof(struct sockaddr_in6));
dst.sin6_family = AF_INET6;
dst.sin6_addr = ip6->ip6_dst;
dst.sin6_scope_id = in6_get_unicast_scopeid(&ip6->ip6_dst, m->m_pkthdr.rcvif);
again:
bzero(&rin6, sizeof(struct route_in6));
dst = (struct sockaddr_in6 *)&rin6.ro_dst;
dst->sin6_len = sizeof(struct sockaddr_in6);
dst->sin6_family = AF_INET6;
dst->sin6_addr = ip6->ip6_dst;
again2:
rin6.ro_rt = in6_rtalloc1((struct sockaddr *)dst, 0, 0, M_GETFIB(m));
rt = rin6.ro_rt;
if (rin6.ro_rt != NULL)
RT_UNLOCK(rin6.ro_rt);
else {
nh = fib6_lookup(M_GETFIB(m), &dst.sin6_addr, dst.sin6_scope_id,
NHR_REF, m->m_pkthdr.flowid);
if (nh == NULL) {
IP6STAT_INC(ip6s_noroute);
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
if (mcopy) {
@ -191,26 +201,15 @@ ip6_forward(struct mbuf *m, int srcrt)
* destination for the reason that the destination is beyond the scope
* of the source address, discard the packet and return an icmp6
* destination unreachable error with Code 2 (beyond scope of source
* address). We use a local copy of ip6_src, since in6_setscope()
* will possibly modify its first argument.
* address).
* [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1]
*/
src_in6 = ip6->ip6_src;
if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) {
/* XXX: this should not happen */
IP6STAT_INC(ip6s_cantforward);
IP6STAT_INC(ip6s_badscope);
goto bad;
}
if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) {
IP6STAT_INC(ip6s_cantforward);
IP6STAT_INC(ip6s_badscope);
goto bad;
}
outzone = in6_get_unicast_scopeid(&ip6->ip6_src, nh->nh_ifp);
inzone = in6_get_unicast_scopeid(&ip6->ip6_src, m->m_pkthdr.rcvif);
if (inzone != outzone) {
IP6STAT_INC(ip6s_cantforward);
IP6STAT_INC(ip6s_badscope);
in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard);
in6_ifstat_inc(nh->nh_ifp, ifs6_in_discard);
if (V_ip6_log_time + V_ip6_log_interval < time_uptime) {
V_ip6_log_time = time_uptime;
@ -220,7 +219,7 @@ ip6_forward(struct mbuf *m, int srcrt)
ip6_sprintf(ip6bufs, &ip6->ip6_src),
ip6_sprintf(ip6bufd, &ip6->ip6_dst),
ip6->ip6_nxt,
if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp));
if_name(m->m_pkthdr.rcvif), if_name(nh->nh_ifp));
}
if (mcopy)
icmp6_error(mcopy, ICMP6_DST_UNREACH,
@ -235,17 +234,21 @@ ip6_forward(struct mbuf *m, int srcrt)
* we need an explicit check because we may mistakenly forward the
* packet to a different zone by (e.g.) a default route.
*/
dst_in6 = ip6->ip6_dst;
if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 ||
in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 ||
inzone != outzone) {
inzone = in6_get_unicast_scopeid(&ip6->ip6_dst, m->m_pkthdr.rcvif);
outzone = in6_get_unicast_scopeid(&ip6->ip6_dst, nh->nh_ifp);
if (inzone != outzone) {
IP6STAT_INC(ip6s_cantforward);
IP6STAT_INC(ip6s_badscope);
goto bad;
}
if (rt->rt_flags & RTF_GATEWAY)
dst = (struct sockaddr_in6 *)rt->rt_gateway;
if (nh->nh_flags & NHF_GATEWAY) {
/* Store gateway address in deembedded form */
dst.sin6_addr = nh->gw6_sa.sin6_addr;
dst.sin6_scope_id = ntohs(in6_getscope(&dst.sin6_addr));
in6_clearscope(&dst.sin6_addr);
}
/*
* If we are to forward the packet using the same interface
@ -256,9 +259,9 @@ ip6_forward(struct mbuf *m, int srcrt)
* Also, don't send redirect if forwarding using a route
* modified by a redirect.
*/
if (V_ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt &&
(rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) {
if (V_ip6_sendredirects && nh->nh_ifp == m->m_pkthdr.rcvif && !srcrt &&
(nh->nh_flags & NHF_REDIRECT) == 0) {
if ((nh->nh_ifp->if_flags & IFF_POINTOPOINT) != 0) {
/*
* If the incoming interface is equal to the outgoing
* one, and the link attached to the interface is
@ -284,7 +287,7 @@ ip6_forward(struct mbuf *m, int srcrt)
* link identifiers, we can do this stuff after making a copy for
* returning an error.
*/
if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
if ((nh->nh_ifp->if_flags & IFF_LOOPBACK) != 0) {
/*
* See corresponding comments in ip6_output.
* XXX: but is it possible that ip6_forward() sends a packet
@ -305,14 +308,14 @@ ip6_forward(struct mbuf *m, int srcrt)
ip6_sprintf(ip6bufs, &ip6->ip6_src),
ip6_sprintf(ip6bufd, &ip6->ip6_dst),
ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
if_name(rt->rt_ifp));
if_name(nh->nh_ifp));
}
/* we can just use rcvif in forwarding. */
origifp = m->m_pkthdr.rcvif;
}
else
origifp = rt->rt_ifp;
origifp = nh->nh_ifp;
/*
* clear embedded scope identifiers if necessary.
* in6_clearscope will touch the addresses only when necessary.
@ -326,7 +329,7 @@ ip6_forward(struct mbuf *m, int srcrt)
odst = ip6->ip6_dst;
/* Run through list of hooks for forwarded packets. */
if (pfil_run_hooks(V_inet6_pfil_head, &m, rt->rt_ifp, PFIL_OUT |
if (pfil_run_hooks(V_inet6_pfil_head, &m, nh->nh_ifp, PFIL_OUT |
PFIL_FWD, NULL) != PFIL_PASS)
goto freecopy;
ip6 = mtod(m, struct ip6_hdr *);
@ -338,7 +341,12 @@ ip6_forward(struct mbuf *m, int srcrt)
if (in6_localip(&ip6->ip6_dst))
m->m_flags |= M_FASTFWD_OURS;
else {
RTFREE(rt);
NH_FREE(nh);
/* Update address and scopeid. Assume scope is embedded */
dst.sin6_scope_id = ntohs(in6_getscope(&ip6->ip6_dst));
dst.sin6_addr = ip6->ip6_dst;
in6_clearscope(&dst.sin6_addr);
goto again; /* Redo the routing table lookup. */
}
}
@ -362,32 +370,43 @@ ip6_forward(struct mbuf *m, int srcrt)
/* Or forward to some other address? */
if ((m->m_flags & M_IP6_NEXTHOP) &&
(fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
dst = (struct sockaddr_in6 *)&rin6.ro_dst;
bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in6));
struct sockaddr_in6 *gw6 = (struct sockaddr_in6 *)(fwd_tag + 1);
/* Update address and scopeid. Assume scope is embedded */
dst.sin6_scope_id = ntohs(in6_getscope(&gw6->sin6_addr));
dst.sin6_addr = gw6->sin6_addr;
in6_clearscope(&dst.sin6_addr);
m->m_flags |= M_SKIP_FIREWALL;
m->m_flags &= ~M_IP6_NEXTHOP;
m_tag_delete(m, fwd_tag);
RTFREE(rt);
goto again2;
NH_FREE(nh);
goto again;
}
pass:
/* See if the size was changed by the packet filter. */
if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
/* TODO: change to nh->nh_mtu */
if (m->m_pkthdr.len > IN6_LINKMTU(nh->nh_ifp)) {
in6_ifstat_inc(nh->nh_ifp, ifs6_in_toobig);
if (mcopy)
icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0,
IN6_LINKMTU(rt->rt_ifp));
IN6_LINKMTU(nh->nh_ifp));
goto bad;
}
error = nd6_output_ifp(rt->rt_ifp, origifp, m, dst, NULL);
/* Currently LLE layer stores embedded IPv6 addresses */
if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6_addr)) {
in6_set_unicast_scopeid(&dst.sin6_addr, dst.sin6_scope_id);
dst.sin6_scope_id = 0;
}
error = nd6_output_ifp(nh->nh_ifp, origifp, m, &dst, NULL);
if (error) {
in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard);
in6_ifstat_inc(nh->nh_ifp, ifs6_out_discard);
IP6STAT_INC(ip6s_cantforward);
} else {
IP6STAT_INC(ip6s_forward);
in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward);
in6_ifstat_inc(nh->nh_ifp, ifs6_out_forward);
if (type)
IP6STAT_INC(ip6s_redirectsent);
else {
@ -401,7 +420,7 @@ ip6_forward(struct mbuf *m, int srcrt)
switch (error) {
case 0:
if (type == ND_REDIRECT) {
icmp6_redirect_output(mcopy, rt->rt_nhop);
icmp6_redirect_output(mcopy, nh);
goto out;
}
goto freecopy;
@ -432,6 +451,6 @@ ip6_forward(struct mbuf *m, int srcrt)
bad:
m_freem(m);
out:
if (rt != NULL)
RTFREE(rt);
if (nh != NULL)
NH_FREE(nh);
}

22
sys/netinet6/scope6.c
View File

@ -465,6 +465,28 @@ in6_getscope(const struct in6_addr *in6)
return (0);
}
/*
* Returns scope zone id for the unicast address @in6.
*
* Returns 0 for global unicast and loopback addresses.
* Returns interface index for the link-local addresses.
*/
uint32_t
in6_get_unicast_scopeid(const struct in6_addr *in6, const struct ifnet *ifp)
{
if (IN6_IS_SCOPE_LINKLOCAL(in6))
return (ifp->if_index);
return (0);
}
void
in6_set_unicast_scopeid(struct in6_addr *in6, uint32_t scopeid)
{
in6->s6_addr16[1] = htons(scopeid & 0xffff);
}
/*
* Return pointer to ifnet structure, corresponding to the zone id of
* link-local scope.

2
sys/netinet6/scope6_var.h
View File

@ -67,6 +67,8 @@ uint16_t in6_getscope(const struct in6_addr *);
uint32_t in6_getscopezone(const struct ifnet *, int);
void in6_splitscope(const struct in6_addr *, struct in6_addr *, uint32_t *);
struct ifnet* in6_getlinkifnet(uint32_t);
uint32_t in6_get_unicast_scopeid(const struct in6_addr *, const struct ifnet *);
void in6_set_unicast_scopeid(struct in6_addr *, uint32_t);
#endif /* _KERNEL */
#endif /* _NETINET6_SCOPE6_VAR_H_ */