One of my trees now contain all the necessary plumbing to run the IPv6
forwarding path (mostly) without holding the KERNEL_LOCK. In other
words we should be able to unlock IPv6 and legacy IP at the same time.
However it's a bit tricky to enqueue packets for local delivery in IPv6
because of the Hop-by-Hop options header processing. So the solution I
came up with is to delay the option parsing a bit and call it ether from
the forwarding path or from the local delivery path. In order to do
that without code duplication, I introduced the function below.
This should be straightforward, ok?
Index: netinet6/ip6_input.c
===================================================================
RCS file: /cvs/src/sys/netinet6/ip6_input.c,v
retrieving revision 1.160
diff -u -p -r1.160 ip6_input.c
--- netinet6/ip6_input.c 19 May 2016 11:34:40 -0000 1.160
+++ netinet6/ip6_input.c 4 Jul 2016 10:50:35 -0000
@@ -122,6 +122,7 @@ struct ip6stat ip6stat;
void ip6_init2(void *);
int ip6_check_rh0hdr(struct mbuf *, int *);
+int ip6_hbhchcheck(struct mbuf *, int *, int *, int *);
int ip6_hopopts_input(u_int32_t *, u_int32_t *, struct mbuf **, int *);
struct mbuf *ip6_pullexthdr(struct mbuf *, size_t, int);
@@ -192,7 +193,6 @@ ip6_input(struct mbuf *m)
struct ip6_hdr *ip6;
int off, nest;
u_int16_t src_scope, dst_scope;
- u_int32_t plen, rtalert = ~0;
int nxt, ours = 0;
#if NPF > 0
struct in6_addr odst;
@@ -495,76 +495,10 @@ ip6_input(struct mbuf *m)
}
hbhcheck:
- /*
- * Process Hop-by-Hop options header if it's contained.
- * m may be modified in ip6_hopopts_input().
- * If a JumboPayload option is included, plen will also be modified.
- */
- plen = (u_int32_t)ntohs(ip6->ip6_plen);
- off = sizeof(struct ip6_hdr);
- if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
- struct ip6_hbh *hbh;
-
- if (ip6_hopopts_input(&plen, &rtalert, &m, &off)) {
- if_put(ifp);
- return; /* m have already been freed */
- }
- /* adjust pointer */
- ip6 = mtod(m, struct ip6_hdr *);
-
- /*
- * if the payload length field is 0 and the next header field
- * indicates Hop-by-Hop Options header, then a Jumbo Payload
- * option MUST be included.
- */
- if (ip6->ip6_plen == 0 && plen == 0) {
- /*
- * Note that if a valid jumbo payload option is
- * contained, ip6_hopopts_input() must set a valid
- * (non-zero) payload length to the variable plen.
- */
- ip6stat.ip6s_badoptions++;
- icmp6_error(m, ICMP6_PARAM_PROB,
- ICMP6_PARAMPROB_HEADER,
- (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
- if_put(ifp);
- return;
- }
- IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
- sizeof(struct ip6_hbh));
- if (hbh == NULL) {
- ip6stat.ip6s_tooshort++;
- if_put(ifp);
- return;
- }
- nxt = hbh->ip6h_nxt;
-
- /*
- * accept the packet if a router alert option is included
- * and we act as an IPv6 router.
- */
- if (rtalert != ~0 && ip6_forwarding)
- ours = 1;
- } else
- nxt = ip6->ip6_nxt;
-
- /*
- * Check that the amount of data in the buffers
- * is as at least much as the IPv6 header would have us expect.
- * Trim mbufs if longer than we expect.
- * Drop packet if shorter than we expect.
- */
- if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
- ip6stat.ip6s_tooshort++;
- goto bad;
- }
- if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
- if (m->m_len == m->m_pkthdr.len) {
- m->m_len = sizeof(struct ip6_hdr) + plen;
- m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
- } else
- m_adj(m, sizeof(struct ip6_hdr) + plen -
m->m_pkthdr.len);
+ if (ip6_hbhchcheck(m, &off, &nxt, &ours)) {
+ if_put(ifp);
+ return; /* m have already been freed */
}
/*
@@ -640,6 +574,93 @@ ip6_input(struct mbuf *m)
m_freem(m);
}
+int
+ip6_hbhchcheck(struct mbuf *m, int *offp, int *nxtp, int *oursp)
+{
+ struct ip6_hdr *ip6;
+ u_int32_t plen, rtalert = ~0;
+ int ours, off, nxt;
+
+ ip6 = mtod(m, struct ip6_hdr *);
+
+ /*
+ * Process Hop-by-Hop options header if it's contained.
+ * m may be modified in ip6_hopopts_input().
+ * If a JumboPayload option is included, plen will also be modified.
+ */
+ plen = (u_int32_t)ntohs(ip6->ip6_plen);
+ off = sizeof(struct ip6_hdr);
+ if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
+ struct ip6_hbh *hbh;
+
+ if (ip6_hopopts_input(&plen, &rtalert, &m, &off)) {
+ return (-1); /* m have already been freed */
+ }
+
+ /* adjust pointer */
+ ip6 = mtod(m, struct ip6_hdr *);
+
+ /*
+ * if the payload length field is 0 and the next header field
+ * indicates Hop-by-Hop Options header, then a Jumbo Payload
+ * option MUST be included.
+ */
+ if (ip6->ip6_plen == 0 && plen == 0) {
+ /*
+ * Note that if a valid jumbo payload option is
+ * contained, ip6_hopopts_input() must set a valid
+ * (non-zero) payload length to the variable plen.
+ */
+ ip6stat.ip6s_badoptions++;
+ icmp6_error(m, ICMP6_PARAM_PROB,
+ ICMP6_PARAMPROB_HEADER,
+ (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
+ return (-1);
+ }
+ IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
+ sizeof(struct ip6_hbh));
+ if (hbh == NULL) {
+ ip6stat.ip6s_tooshort++;
+ return (-1);
+ }
+ nxt = hbh->ip6h_nxt;
+
+ /*
+ * accept the packet if a router alert option is included
+ * and we act as an IPv6 router.
+ */
+ if (rtalert != ~0 && ip6_forwarding)
+ ours = 1;
+ } else
+ nxt = ip6->ip6_nxt;
+
+ /*
+ * Check that the amount of data in the buffers
+ * is as at least much as the IPv6 header would have us expect.
+ * Trim mbufs if longer than we expect.
+ * Drop packet if shorter than we expect.
+ */
+ if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
+ ip6stat.ip6s_tooshort++;
+ m_freem(m);
+ return (-1);
+ }
+ if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
+ if (m->m_len == m->m_pkthdr.len) {
+ m->m_len = sizeof(struct ip6_hdr) + plen;
+ m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
+ } else {
+ m_adj(m,
+ sizeof(struct ip6_hdr) + plen - m->m_pkthdr.len);
+ }
+ }
+
+ *offp = off;
+ *nxtp = nxt;
+ *oursp = ours;
+
+ return (0);
+}
/* scan packet for RH0 routing header. Mostly stolen from pf.c:pf_test() */
int
ip6_check_rh0hdr(struct mbuf *m, int *offp)
