slirp: Factorizing tcpiphdr structure with an union
This patch factorizes the tcpiphdr structure to put the IPv4 fields in an union, for addition of version 6 in further patch. Using some macros, retrocompatibility of the existing code is assured. This patch also fixes the SLIRP_MSIZE and margin computation in various functions, and makes them compatible with the new tcpiphdr structure, whose size will be bigger than sizeof(struct tcphdr) + sizeof(struct ip) Signed-off-by: Guillaume Subiron <maethor@subiron.org> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Reviewed-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Guillaume Subiron
Samuel Thibault
parent
15d62af4b6
commit
98c63057d2
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@ -17,7 +17,7 @@
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#define IF_MRU 1500
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#define IF_COMP IF_AUTOCOMP /* Flags for compression */
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/* 2 for alignment, 14 for ethernet, 40 for TCP/IP */
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#define IF_MAXLINKHDR (2 + 14 + 40)
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/* 2 for alignment, 14 for ethernet */
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#define IF_MAXLINKHDR (2 + ETH_HLEN)
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#endif
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@ -22,9 +22,9 @@
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/*
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* Find a nice value for msize
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* XXX if_maxlinkhdr already in mtu
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*/
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#define SLIRP_MSIZE (IF_MTU + IF_MAXLINKHDR + offsetof(struct mbuf, m_dat) + 6)
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#define SLIRP_MSIZE\
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(offsetof(struct mbuf, m_dat) + IF_MAXLINKHDR + TCPIPHDR_DELTA + IF_MTU)
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void
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m_init(Slirp *slirp)
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@ -766,15 +766,16 @@ void slirp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len)
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m = m_get(slirp);
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if (!m)
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return;
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/* Note: we add to align the IP header */
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if (M_FREEROOM(m) < pkt_len + 2) {
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m_inc(m, pkt_len + 2);
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/* Note: we add 2 to align the IP header on 4 bytes,
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* and add the margin for the tcpiphdr overhead */
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if (M_FREEROOM(m) < pkt_len + TCPIPHDR_DELTA + 2) {
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m_inc(m, pkt_len + TCPIPHDR_DELTA + 2);
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}
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m->m_len = pkt_len + 2;
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memcpy(m->m_data + 2, pkt, pkt_len);
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m->m_len = pkt_len + TCPIPHDR_DELTA + 2;
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memcpy(m->m_data + TCPIPHDR_DELTA + 2, pkt, pkt_len);
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m->m_data += 2 + ETH_HLEN;
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m->m_len -= 2 + ETH_HLEN;
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m->m_data += TCPIPHDR_DELTA + 2 + ETH_HLEN;
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m->m_len -= TCPIPHDR_DELTA + 2 + ETH_HLEN;
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if (proto == ETH_P_IP) {
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ip_input(m);
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@ -483,7 +483,18 @@ sorecvfrom(struct socket *so)
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if (!m) {
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return;
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}
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m->m_data += IF_MAXLINKHDR;
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switch (so->so_ffamily) {
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case AF_INET:
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m->m_data += IF_MAXLINKHDR + sizeof(struct udpiphdr);
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break;
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case AF_INET6:
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m->m_data += IF_MAXLINKHDR + sizeof(struct ip6)
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+ sizeof(struct udphdr);
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break;
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default:
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g_assert_not_reached();
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break;
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}
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/*
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* XXX Shouldn't FIONREAD packets destined for port 53,
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@ -256,11 +256,6 @@ tcp_input(struct mbuf *m, int iphlen, struct socket *inso)
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}
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slirp = m->slirp;
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/*
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* Get IP and TCP header together in first mbuf.
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* Note: IP leaves IP header in first mbuf.
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*/
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ti = mtod(m, struct tcpiphdr *);
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if (iphlen > sizeof(struct ip )) {
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ip_stripoptions(m, (struct mbuf *)0);
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iphlen=sizeof(struct ip );
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@ -276,15 +271,29 @@ tcp_input(struct mbuf *m, int iphlen, struct socket *inso)
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save_ip = *ip;
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save_ip.ip_len+= iphlen;
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/*
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* Get IP and TCP header together in first mbuf.
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* Note: IP leaves IP header in first mbuf.
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*/
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m->m_data -= sizeof(struct tcpiphdr) - sizeof(struct ip)
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- sizeof(struct tcphdr);
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m->m_len += sizeof(struct tcpiphdr) - sizeof(struct ip)
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- sizeof(struct tcphdr);
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ti = mtod(m, struct tcpiphdr *);
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/*
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* Checksum extended TCP header and data.
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*/
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tlen = ((struct ip *)ti)->ip_len;
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tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
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memset(&ti->ti_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
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ti->ti_x1 = 0;
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tlen = ip->ip_len;
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tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
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memset(&ti->ih_mbuf, 0 , sizeof(struct mbuf_ptr));
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memset(&ti->ti, 0, sizeof(ti->ti));
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ti->ti_x0 = 0;
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ti->ti_src = save_ip.ip_src;
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ti->ti_dst = save_ip.ip_dst;
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ti->ti_pr = save_ip.ip_p;
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ti->ti_len = htons((uint16_t)tlen);
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len = sizeof(struct ip ) + tlen;
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len = ((sizeof(struct tcpiphdr) - sizeof(struct tcphdr)) + tlen);
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if(cksum(m, len)) {
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goto drop;
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}
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@ -603,6 +612,10 @@ findso:
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HTONS(ti->ti_urp);
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m->m_data -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
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m->m_len += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
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m->m_data += sizeof(struct tcpiphdr) - sizeof(struct ip)
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- sizeof(struct tcphdr);
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m->m_len -= sizeof(struct tcpiphdr) - sizeof(struct ip)
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- sizeof(struct tcphdr);
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*ip=save_ip;
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icmp_send_error(m, ICMP_UNREACH, code, 0, strerror(errno));
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}
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@ -1471,7 +1484,7 @@ tcp_mss(struct tcpcb *tp, u_int offer)
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DEBUG_ARG("tp = %p", tp);
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DEBUG_ARG("offer = %d", offer);
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mss = min(IF_MTU, IF_MRU) - sizeof(struct tcpiphdr);
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mss = min(IF_MTU, IF_MRU) - sizeof(struct tcphdr) + sizeof(struct ip);
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if (offer)
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mss = min(mss, offer);
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mss = max(mss, 32);
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@ -448,15 +448,23 @@ send:
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*/
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m->m_len = hdrlen + len; /* XXX Needed? m_len should be correct */
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{
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struct tcpiphdr tcpiph_save = *(mtod(m, struct tcpiphdr *));
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m->m_data += sizeof(struct tcpiphdr) - sizeof(struct tcphdr)
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- sizeof(struct ip);
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m->m_len -= sizeof(struct tcpiphdr) - sizeof(struct tcphdr)
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- sizeof(struct ip);
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struct ip *ip = mtod(m, struct ip *);
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((struct ip *)ti)->ip_len = m->m_len;
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ip->ip_len = m->m_len;
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ip->ip_dst = tcpiph_save.ti_dst;
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ip->ip_src = tcpiph_save.ti_src;
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ip->ip_p = tcpiph_save.ti_pr;
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((struct ip *)ti)->ip_ttl = IPDEFTTL;
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((struct ip *)ti)->ip_tos = so->so_iptos;
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ip->ip_ttl = IPDEFTTL;
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ip->ip_tos = so->so_iptos;
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error = ip_output(so, m);
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}
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if (error) {
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out:
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return (error);
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@ -76,9 +76,10 @@ tcp_template(struct tcpcb *tp)
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register struct tcpiphdr *n = &tp->t_template;
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n->ti_mbuf = NULL;
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n->ti_x1 = 0;
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memset(&n->ti, 0, sizeof(n->ti));
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n->ti_x0 = 0;
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n->ti_pr = IPPROTO_TCP;
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n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
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n->ti_len = htons(sizeof(struct tcphdr));
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n->ti_src = so->so_faddr;
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n->ti_dst = so->so_laddr;
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n->ti_sport = so->so_fport;
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@ -131,6 +132,7 @@ tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
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m->m_data += IF_MAXLINKHDR;
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*mtod(m, struct tcpiphdr *) = *ti;
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ti = mtod(m, struct tcpiphdr *);
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memset(&ti->ti, 0, sizeof(ti->ti));
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flags = TH_ACK;
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} else {
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/*
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@ -150,8 +152,8 @@ tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
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tlen += sizeof (struct tcpiphdr);
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m->m_len = tlen;
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ti->ti_mbuf = NULL;
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ti->ti_x1 = 0;
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ti->ti_mbuf = NULL;
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ti->ti_x0 = 0;
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ti->ti_seq = htonl(seq);
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ti->ti_ack = htonl(ack);
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ti->ti_x2 = 0;
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@ -164,12 +166,23 @@ tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
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ti->ti_urp = 0;
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ti->ti_sum = 0;
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ti->ti_sum = cksum(m, tlen);
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((struct ip *)ti)->ip_len = tlen;
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if(flags & TH_RST)
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((struct ip *)ti)->ip_ttl = MAXTTL;
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else
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((struct ip *)ti)->ip_ttl = IPDEFTTL;
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struct tcpiphdr tcpiph_save = *(mtod(m, struct tcpiphdr *));
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m->m_data += sizeof(struct tcpiphdr) - sizeof(struct tcphdr)
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- sizeof(struct ip);
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m->m_len -= sizeof(struct tcpiphdr) - sizeof(struct tcphdr)
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- sizeof(struct ip);
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struct ip *ip = mtod(m, struct ip *);
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ip->ip_len = tlen;
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ip->ip_dst = tcpiph_save.ti_dst;
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ip->ip_src = tcpiph_save.ti_src;
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ip->ip_p = tcpiph_save.ti_pr;
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if (flags & TH_RST) {
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ip->ip_ttl = MAXTTL;
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} else {
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ip->ip_ttl = IPDEFTTL;
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}
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(void) ip_output((struct socket *)0, m);
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}
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@ -37,15 +37,23 @@
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* Tcp+ip header, after ip options removed.
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*/
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struct tcpiphdr {
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struct ipovly ti_i; /* overlaid ip structure */
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struct tcphdr ti_t; /* tcp header */
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struct mbuf_ptr ih_mbuf; /* backpointer to mbuf */
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union {
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struct {
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struct in_addr ih_src; /* source internet address */
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struct in_addr ih_dst; /* destination internet address */
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uint8_t ih_x1; /* (unused) */
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uint8_t ih_pr; /* protocol */
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} ti_i4;
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} ti;
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uint16_t ti_x0;
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uint16_t ti_len; /* protocol length */
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struct tcphdr ti_t; /* tcp header */
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};
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#define ti_mbuf ti_i.ih_mbuf.mptr
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#define ti_x1 ti_i.ih_x1
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#define ti_pr ti_i.ih_pr
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#define ti_len ti_i.ih_len
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#define ti_src ti_i.ih_src
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#define ti_dst ti_i.ih_dst
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#define ti_mbuf ih_mbuf.mptr
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#define ti_pr ti.ti_i4.ih_pr
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#define ti_src ti.ti_i4.ih_src
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#define ti_dst ti.ti_i4.ih_dst
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#define ti_sport ti_t.th_sport
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#define ti_dport ti_t.th_dport
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#define ti_seq ti_t.th_seq
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@ -65,6 +73,13 @@ struct tcpiphdr {
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#define tcpfrag_list_end(F, T) (tcpiphdr2qlink(F) == (struct qlink*)(T))
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#define tcpfrag_list_empty(T) ((T)->seg_next == (struct tcpiphdr*)(T))
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/* This is the difference between the size of a tcpiphdr structure, and the
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* size of actual ip+tcp headers, rounded up since we need to align data. */
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#define TCPIPHDR_DELTA\
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(max(0,\
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(sizeof(struct tcpiphdr)\
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- sizeof(struct ip) - sizeof(struct tcphdr) + 3) & ~3))
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/*
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* Just a clean way to get to the first byte
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* of the packet
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