From fc6c9257c6dd47316a1c55d356bcd89bdc5fd642 Mon Sep 17 00:00:00 2001 From: Yann Bordenave Date: Tue, 15 Mar 2016 10:31:19 +0100 Subject: [PATCH] slirp: Adding ICMPv6 error sending Adding icmp6_send_error to send ICMPv6 Error messages. This function is simpler than the v4 version. Adding some calls in various functions to send ICMP errors, when a received packet is too big, or when its hop limit is 0. Signed-off-by: Yann Bordenave Signed-off-by: Samuel Thibault Reviewed-by: Thomas Huth --- slirp/ip6_icmp.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++ slirp/ip6_icmp.h | 10 +++++++ slirp/ip6_input.c | 11 +++++--- 3 files changed, 84 insertions(+), 3 deletions(-) diff --git a/slirp/ip6_icmp.c b/slirp/ip6_icmp.c index 9f3fd4a332..9d61349c7d 100644 --- a/slirp/ip6_icmp.c +++ b/slirp/ip6_icmp.c @@ -60,6 +60,72 @@ static void icmp6_send_echoreply(struct mbuf *m, Slirp *slirp, struct ip6 *ip, ip6_output(NULL, t, 0); } +void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code) +{ + Slirp *slirp = m->slirp; + struct mbuf *t; + struct ip6 *ip = mtod(m, struct ip6 *); + + DEBUG_CALL("icmp6_send_error"); + DEBUG_ARGS((dfd, " type = %d, code = %d\n", type, code)); + + if (IN6_IS_ADDR_MULTICAST(&ip->ip_src) || + IN6_IS_ADDR_UNSPECIFIED(&ip->ip_src)) { + /* TODO icmp error? */ + return; + } + + t = m_get(slirp); + + /* IPv6 packet */ + struct ip6 *rip = mtod(t, struct ip6 *); + rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR; + rip->ip_dst = ip->ip_src; +#if !defined(_WIN32) || (_WIN32_WINNT >= 0x0600) + char addrstr[INET6_ADDRSTRLEN]; + inet_ntop(AF_INET6, &rip->ip_dst, addrstr, INET6_ADDRSTRLEN); + DEBUG_ARG("target = %s", addrstr); +#endif + + rip->ip_nh = IPPROTO_ICMPV6; + const int error_data_len = min(m->m_len, + IF_MTU - (sizeof(struct ip6) + ICMP6_ERROR_MINLEN)); + rip->ip_pl = htons(ICMP6_ERROR_MINLEN + error_data_len); + t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl); + + /* ICMPv6 packet */ + t->m_data += sizeof(struct ip6); + struct icmp6 *ricmp = mtod(t, struct icmp6 *); + ricmp->icmp6_type = type; + ricmp->icmp6_code = code; + ricmp->icmp6_cksum = 0; + + switch (type) { + case ICMP6_UNREACH: + case ICMP6_TIMXCEED: + ricmp->icmp6_err.unused = 0; + break; + case ICMP6_TOOBIG: + ricmp->icmp6_err.mtu = htonl(IF_MTU); + break; + case ICMP6_PARAMPROB: + /* TODO: Handle this case */ + break; + default: + g_assert_not_reached(); + break; + } + t->m_data += ICMP6_ERROR_MINLEN; + memcpy(t->m_data, m->m_data, error_data_len); + + /* Checksum */ + t->m_data -= ICMP6_ERROR_MINLEN; + t->m_data -= sizeof(struct ip6); + ricmp->icmp6_cksum = ip6_cksum(t); + + ip6_output(NULL, t, 0); +} + /* * Send NDP Router Advertisement */ diff --git a/slirp/ip6_icmp.h b/slirp/ip6_icmp.h index b2c40d6c96..9460bf837a 100644 --- a/slirp/ip6_icmp.h +++ b/slirp/ip6_icmp.h @@ -19,6 +19,12 @@ struct icmp6_echo { /* Echo Messages */ uint16_t seq_num; }; +union icmp6_error_body { + uint32_t unused; + uint32_t pointer; + uint32_t mtu; +}; + /* * NDP Messages */ @@ -82,6 +88,7 @@ struct icmp6 { uint8_t icmp6_code; /* type sub code */ uint16_t icmp6_cksum; /* ones complement cksum of struct */ union { + union icmp6_error_body error_body; struct icmp6_echo echo; struct ndp_rs ndp_rs; struct ndp_ra ndp_ra; @@ -89,6 +96,7 @@ struct icmp6 { struct ndp_na ndp_na; struct ndp_redirect ndp_redirect; } icmp6_body; +#define icmp6_err icmp6_body.error_body #define icmp6_echo icmp6_body.echo #define icmp6_nrs icmp6_body.ndp_rs #define icmp6_nra icmp6_body.ndp_ra @@ -98,6 +106,7 @@ struct icmp6 { } QEMU_PACKED; #define ICMP6_MINLEN 4 +#define ICMP6_ERROR_MINLEN 8 #define ICMP6_ECHO_MINLEN 8 #define ICMP6_NDP_RS_MINLEN 8 #define ICMP6_NDP_RA_MINLEN 16 @@ -197,6 +206,7 @@ struct ndpopt { void icmp6_init(Slirp *slirp); void icmp6_cleanup(Slirp *slirp); void icmp6_input(struct mbuf *); +void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code); void ndp_send_ra(Slirp *slirp); void ndp_send_ns(Slirp *slirp, struct in6_addr addr); diff --git a/slirp/ip6_input.c b/slirp/ip6_input.c index ca0007c14c..b6a438d7af 100644 --- a/slirp/ip6_input.c +++ b/slirp/ip6_input.c @@ -39,9 +39,14 @@ void ip6_input(struct mbuf *m) goto bad; } + if (ntohs(ip6->ip_pl) > IF_MTU) { + icmp6_send_error(m, ICMP6_TOOBIG, 0); + goto bad; + } + /* check ip_ttl for a correct ICMP reply */ if (ip6->ip_hl == 0) { - /*icmp_send_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");*/ + icmp6_send_error(m, ICMP6_TIMXCEED, ICMP6_TIMXCEED_INTRANS); goto bad; } @@ -50,10 +55,10 @@ void ip6_input(struct mbuf *m) */ switch (ip6->ip_nh) { case IPPROTO_TCP: - /*tcp_input(m, hlen, (struct socket *)NULL);*/ + icmp6_send_error(m, ICMP6_UNREACH, ICMP6_UNREACH_NO_ROUTE); break; case IPPROTO_UDP: - /*udp_input(m, hlen);*/ + icmp6_send_error(m, ICMP6_UNREACH, ICMP6_UNREACH_NO_ROUTE); break; case IPPROTO_ICMPV6: icmp6_input(m);