Re: etherip alignment issues

[YASUOKA Masahiko]

Hi,

I could repeat the problem on my octeon.  Tested the diff on it.

ok?

Use a new mbufs for a tunnel header to make sure it is aligned correctly.

Index: sys/net/if_etherip.c
===================================================================
RCS file: /cvs/src/sys/net/if_etherip.c,v
retrieving revision 1.7
diff -u -p -r1.7 if_etherip.c
--- sys/net/if_etherip.c        13 Apr 2016 11:41:15 -0000      1.7
+++ sys/net/if_etherip.c        26 Sep 2016 01:20:08 -0000
@@ -354,6 +354,7 @@ ip_etherip_output(struct ifnet *ifp, str
        struct sockaddr_in *src, *dst;
        struct etherip_header *eip;
        struct ip *ip;
+       struct mbuf *m0;
 
        src = (struct sockaddr_in *)&sc->sc_src;
        dst = (struct sockaddr_in *)&sc->sc_dst;
@@ -370,24 +371,25 @@ ip_etherip_output(struct ifnet *ifp, str
 
        m->m_flags &= ~(M_BCAST|M_MCAST);
 
-       M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
-       if (m == NULL) {
-               etheripstat.etherip_adrops++;
+       MGETHDR(m0, M_DONTWAIT, MT_HEADER);
+       if (m0 == NULL) {
+               m_freem(m);
                return ENOBUFS;
        }
-       eip = mtod(m, struct etherip_header *);
-       eip->eip_ver = ETHERIP_VERSION;
-       eip->eip_res = 0;
-       eip->eip_pad = 0;
+       M_MOVE_HDR(m0, m);
+       m0->m_len = sizeof(struct ip) + sizeof(struct etherip_header);
+       m0->m_pkthdr.len += m0->m_len;
+       m0->m_next = m;
+       m = m0;
 
-       M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
-       if (m == NULL) {
-               etheripstat.etherip_adrops++;
-               return ENOBUFS;
-       }
        ip = mtod(m, struct ip *);
        memset(ip, 0, sizeof(struct ip));
 
+       eip = (struct etherip_header *)(ip + 1);
+       eip->eip_ver = ETHERIP_VERSION;
+       eip->eip_res = 0;
+       eip->eip_pad = 0;
+
        ip->ip_v = IPVERSION;
        ip->ip_hl = sizeof(struct ip) >> 2;
        ip->ip_id = htons(ip_randomid());
@@ -514,6 +516,7 @@ ip6_etherip_output(struct ifnet *ifp, st
        struct sockaddr_in6 *src, *dst;
        struct etherip_header *eip;
        struct ip6_hdr *ip6;
+       struct mbuf *m0;
 
        src = (struct sockaddr_in6 *)&sc->sc_src;
        dst = (struct sockaddr_in6 *)&sc->sc_dst;
@@ -530,22 +533,24 @@ ip6_etherip_output(struct ifnet *ifp, st
 
        m->m_flags &= ~(M_BCAST|M_MCAST);
 
-       M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
-       if (m == NULL) {
-               etheripstat.etherip_adrops++;
+       MGETHDR(m0, M_DONTWAIT, MT_HEADER);
+       if (m0 == NULL) {
+               m_freem(m);
                return ENOBUFS;
        }
-       eip = mtod(m, struct etherip_header *);
+       M_MOVE_PKTHDR(m0, m);
+       m0->m_len = sizeof(struct ip6_hdr) + sizeof(struct etherip_header);
+       m0->m_pkthdr.len += m0->m_len;
+       m0->m_next = m;
+       m = m0;
+
+       ip6 = mtod(m, struct ip6_hdr *);
+
+       eip = (struct etherip_header *)(ip6 + 1);
        eip->eip_ver = ETHERIP_VERSION;
        eip->eip_res = 0;
        eip->eip_pad = 0;
 
-       M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
-       if (m == NULL) {
-               etheripstat.etherip_adrops++;
-               return ENOBUFS;
-       }
-       ip6 = mtod(m, struct ip6_hdr *);
        ip6->ip6_flow = 0;
        ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
        ip6->ip6_vfc |= IPV6_VERSION;