From a2f80fdfc683019901cdf4c0863a5920c0ca7245 Mon Sep 17 00:00:00 2001 From: Samuel Thibault Date: Sun, 26 Mar 2017 20:46:34 +0200 Subject: [PATCH] slirp: Send RDNSS in RA only if host has an IPv6 DNS server MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: Samuel Thibault Reviewed-by: Philippe Mathieu-Daudé --- slirp/ip6_icmp.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/slirp/ip6_icmp.c b/slirp/ip6_icmp.c index d0f5cc1456..777eb574be 100644 --- a/slirp/ip6_icmp.c +++ b/slirp/ip6_icmp.c @@ -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; @@ -189,18 +192,18 @@ 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 */ - struct ndpopt *opt3 = mtod(t, struct ndpopt *); - opt3->ndpopt_type = NDPOPT_RDNSS; - opt3->ndpopt_len = NDPOPT_RDNSS_LEN / 8; - opt3->ndpopt_rdnss.reserved = 0; - opt3->ndpopt_rdnss.lifetime = htonl(2 * NDP_MaxRtrAdvInterval); - opt3->ndpopt_rdnss.addr = slirp->vnameserver_addr6; - t->m_data += NDPOPT_RDNSS_LEN; - pl_size += NDPOPT_RDNSS_LEN; -#endif + 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; + opt3->ndpopt_rdnss.reserved = 0; + opt3->ndpopt_rdnss.lifetime = htonl(2 * NDP_MaxRtrAdvInterval); + opt3->ndpopt_rdnss.addr = slirp->vnameserver_addr6; + t->m_data += NDPOPT_RDNSS_LEN; + pl_size += NDPOPT_RDNSS_LEN; + } rip->ip_pl = htons(pl_size); t->m_data -= sizeof(struct ip6) + pl_size;