Commit a2f80fdf authored by Samuel Thibault's avatar Samuel Thibault
Browse files

slirp: Send RDNSS in RA only if host has an IPv6 DNS server 



Previously we would always send an RDNSS option in the RA, making the guest
try to resolve DNS through IPv6, even if the host does not actually have
and IPv6 DNS server available.

This makes the RDNSS option enabled only when an IPv6 DNS server is
available.

Signed-off-by: default avatarSamuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <f4bug@amsat.org>
parent e42f869b

slirp/ip6_icmp.c

+14 −11
Original line number Diff line number Diff line
@@ -144,6 +144,9 @@ void ndp_send_ra(Slirp *slirp) 
    struct mbuf *t = m_get(slirp);

    struct ip6 *rip = mtod(t, struct ip6 *);

    size_t pl_size = 0;

    struct in6_addr addr;

    uint32_t scope_id;



    rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR;

    rip->ip_dst = (struct in6_addr)ALLNODES_MULTICAST;

    rip->ip_nh = IPPROTO_ICMPV6;
@@ -189,9 +192,9 @@ void ndp_send_ra(Slirp *slirp) 
    t->m_data += NDPOPT_PREFIXINFO_LEN;

    pl_size += NDPOPT_PREFIXINFO_LEN;



#ifndef _WIN32

    /* Prefix information (NDP option) */

    /* disabled for windows for now, until get_dns6_addr is implemented */

    if (get_dns6_addr(&addr, &scope_id) >= 0) {

        /* Host system does have an IPv6 DNS server, announce our proxy.  */

        struct ndpopt *opt3 = mtod(t, struct ndpopt *);

        opt3->ndpopt_type = NDPOPT_RDNSS;

        opt3->ndpopt_len = NDPOPT_RDNSS_LEN / 8;
@@ -200,7 +203,7 @@ void ndp_send_ra(Slirp *slirp) 
        opt3->ndpopt_rdnss.addr = slirp->vnameserver_addr6;

        t->m_data += NDPOPT_RDNSS_LEN;

        pl_size += NDPOPT_RDNSS_LEN;

#endif

    }



    rip->ip_pl = htons(pl_size);

    t->m_data -= sizeof(struct ip6) + pl_size;