Re: [Qemu-devel] [PATCH 1/2] slirp: Make RA build more flexible

[Philippe Mathieu-Daudé]

On 03/26/2017 03:46 PM, Samuel Thibault wrote:

Do not hardcode the RA size at all, use a pl_size variable which
accounts the accumulated size, and fill rip->ip_pl at the end.

This will allow to make some blocks optional.

Signed-off-by: Samuel Thibault 


Reviewed-by: Philippe Mathieu-Daudé 


---
 slirp/ip6_icmp.c | 24 +---
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/slirp/ip6_icmp.c b/slirp/ip6_icmp.c
index 298a48dd25..d0f5cc1456 100644
--- a/slirp/ip6_icmp.c
+++ b/slirp/ip6_icmp.c
@@ -143,17 +143,10 @@ void ndp_send_ra(Slirp *slirp)
 /* Build IPv6 packet */
 struct mbuf *t = m_get(slirp);
 struct ip6 *rip = mtod(t, struct ip6 *);
+size_t pl_size = 0;
 rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR;
 rip->ip_dst = (struct in6_addr)ALLNODES_MULTICAST;
 rip->ip_nh = IPPROTO_ICMPV6;
-rip->ip_pl = htons(ICMP6_NDP_RA_MINLEN
-+ NDPOPT_LINKLAYER_LEN
-+ NDPOPT_PREFIXINFO_LEN
-#ifndef _WIN32
-+ NDPOPT_RDNSS_LEN
-#endif
-);
-t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);

 /* Build ICMPv6 packet */
 t->m_data += sizeof(struct ip6);
@@ -171,6 +164,7 @@ void ndp_send_ra(Slirp *slirp)
 ricmp->icmp6_nra.reach_time = htonl(NDP_AdvReachableTime);
 ricmp->icmp6_nra.retrans_time = htonl(NDP_AdvRetransTime);
 t->m_data += ICMP6_NDP_RA_MINLEN;
+pl_size += ICMP6_NDP_RA_MINLEN;

 /* Source link-layer address (NDP option) */
 struct ndpopt *opt = mtod(t, struct ndpopt *);
@@ -178,6 +172,7 @@ void ndp_send_ra(Slirp *slirp)
 opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
 in6_compute_ethaddr(rip->ip_src, opt->ndpopt_linklayer);
 t->m_data += NDPOPT_LINKLAYER_LEN;
+pl_size += NDPOPT_LINKLAYER_LEN;

 /* Prefix information (NDP option) */
 struct ndpopt *opt2 = mtod(t, struct ndpopt *);
@@ -192,6 +187,7 @@ void ndp_send_ra(Slirp *slirp)
 opt2->ndpopt_prefixinfo.reserved2 = 0;
 opt2->ndpopt_prefixinfo.prefix = slirp->vprefix_addr6;
 t->m_data += NDPOPT_PREFIXINFO_LEN;
+pl_size += NDPOPT_PREFIXINFO_LEN;

 #ifndef _WIN32
 /* Prefix information (NDP option) */
@@ -203,16 +199,14 @@ void ndp_send_ra(Slirp *slirp)
 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

+rip->ip_pl = htons(pl_size);
+t->m_data -= sizeof(struct ip6) + pl_size;
+t->m_len = sizeof(struct ip6) + pl_size;
+
 /* ICMPv6 Checksum */
-#ifndef _WIN32
-t->m_data -= NDPOPT_RDNSS_LEN;
-#endif
-t->m_data -= NDPOPT_PREFIXINFO_LEN;
-t->m_data -= NDPOPT_LINKLAYER_LEN;
-t->m_data -= ICMP6_NDP_RA_MINLEN;
-t->m_data -= sizeof(struct ip6);
 ricmp->icmp6_cksum = ip6_cksum(t);

 ip6_output(NULL, t, 0);

[Qemu-devel] [PATCH 1/2] slirp: Make RA build more flexible

[Samuel Thibault]

Do not hardcode the RA size at all, use a pl_size variable which
accounts the accumulated size, and fill rip->ip_pl at the end.

This will allow to make some blocks optional.

Signed-off-by: Samuel Thibault 
---
 slirp/ip6_icmp.c | 24 +---
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/slirp/ip6_icmp.c b/slirp/ip6_icmp.c
index 298a48dd25..d0f5cc1456 100644
--- a/slirp/ip6_icmp.c
+++ b/slirp/ip6_icmp.c
@@ -143,17 +143,10 @@ void ndp_send_ra(Slirp *slirp)
 /* Build IPv6 packet */
 struct mbuf *t = m_get(slirp);
 struct ip6 *rip = mtod(t, struct ip6 *);
+size_t pl_size = 0;
 rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR;
 rip->ip_dst = (struct in6_addr)ALLNODES_MULTICAST;
 rip->ip_nh = IPPROTO_ICMPV6;
-rip->ip_pl = htons(ICMP6_NDP_RA_MINLEN
-+ NDPOPT_LINKLAYER_LEN
-+ NDPOPT_PREFIXINFO_LEN
-#ifndef _WIN32
-+ NDPOPT_RDNSS_LEN
-#endif
-);
-t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
 
 /* Build ICMPv6 packet */
 t->m_data += sizeof(struct ip6);
@@ -171,6 +164,7 @@ void ndp_send_ra(Slirp *slirp)
 ricmp->icmp6_nra.reach_time = htonl(NDP_AdvReachableTime);
 ricmp->icmp6_nra.retrans_time = htonl(NDP_AdvRetransTime);
 t->m_data += ICMP6_NDP_RA_MINLEN;
+pl_size += ICMP6_NDP_RA_MINLEN;
 
 /* Source link-layer address (NDP option) */
 struct ndpopt *opt = mtod(t, struct ndpopt *);
@@ -178,6 +172,7 @@ void ndp_send_ra(Slirp *slirp)
 opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
 in6_compute_ethaddr(rip->ip_src, opt->ndpopt_linklayer);
 t->m_data += NDPOPT_LINKLAYER_LEN;
+pl_size += NDPOPT_LINKLAYER_LEN;
 
 /* Prefix information (NDP option) */
 struct ndpopt *opt2 = mtod(t, struct ndpopt *);
@@ -192,6 +187,7 @@ void ndp_send_ra(Slirp *slirp)
 opt2->ndpopt_prefixinfo.reserved2 = 0;
 opt2->ndpopt_prefixinfo.prefix = slirp->vprefix_addr6;
 t->m_data += NDPOPT_PREFIXINFO_LEN;
+pl_size += NDPOPT_PREFIXINFO_LEN;
 
 #ifndef _WIN32
 /* Prefix information (NDP option) */
@@ -203,16 +199,14 @@ void ndp_send_ra(Slirp *slirp)
 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
 
+rip->ip_pl = htons(pl_size);
+t->m_data -= sizeof(struct ip6) + pl_size;
+t->m_len = sizeof(struct ip6) + pl_size;
+
 /* ICMPv6 Checksum */
-#ifndef _WIN32
-t->m_data -= NDPOPT_RDNSS_LEN;
-#endif
-t->m_data -= NDPOPT_PREFIXINFO_LEN;
-t->m_data -= NDPOPT_LINKLAYER_LEN;
-t->m_data -= ICMP6_NDP_RA_MINLEN;
-t->m_data -= sizeof(struct ip6);
 ricmp->icmp6_cksum = ip6_cksum(t);
 
 ip6_output(NULL, t, 0);
-- 
2.11.0