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 <maet...@subiron.org>
Signed-off-by: Samuel Thibault <samuel.thiba...@ens-lyon.org>
---
slirp/if.h | 4 ++--
slirp/mbuf.c | 3 ++-
slirp/slirp.c | 15 ++++++++-------
slirp/socket.c | 13 ++++++++++++-
slirp/tcp_input.c | 31 ++++++++++++++++++++-----------
slirp/tcp_output.c | 18 +++++++++++++-----
slirp/tcp_subr.c | 31 ++++++++++++++++++++++---------
slirp/tcpip.h | 31 +++++++++++++++++++++++--------
8 files changed, 102 insertions(+), 44 deletions(-)
diff --git a/slirp/if.h b/slirp/if.h
index 3327023..c7a5c57 100644
--- a/slirp/if.h
+++ b/slirp/if.h
@@ -17,7 +17,7 @@
#define IF_MRU 1500
#define IF_COMP IF_AUTOCOMP /* Flags for compression */
-/* 2 for alignment, 14 for ethernet, 40 for TCP/IP */
-#define IF_MAXLINKHDR (2 + 14 + 40)
+/* 2 for alignment, 14 for ethernet */
+#define IF_MAXLINKHDR (2 + ETH_HLEN)
#endif
diff --git a/slirp/mbuf.c b/slirp/mbuf.c
index 92c429e..87ee550 100644
--- a/slirp/mbuf.c
+++ b/slirp/mbuf.c
@@ -23,7 +23,8 @@
* Find a nice value for msize
* XXX if_maxlinkhdr already in mtu
*/
-#define SLIRP_MSIZE (IF_MTU + IF_MAXLINKHDR + offsetof(struct mbuf, m_dat) + 6)
+#define SLIRP_MSIZE\
+ (offsetof(struct mbuf, m_dat) + IF_MAXLINKHDR + TCPIPHDR_DELTA + IF_MTU)
void
m_init(Slirp *slirp)
diff --git a/slirp/slirp.c b/slirp/slirp.c
index a78fa72..79025cd 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -756,15 +756,16 @@ void slirp_input(Slirp *slirp, const uint8_t *pkt, int
pkt_len)
m = m_get(slirp);
if (!m)
return;
- /* Note: we add to align the IP header */
- if (M_FREEROOM(m) < pkt_len + 2) {
- m_inc(m, pkt_len + 2);
+ /* Note: we add 2 to align the IP header on 4 bytes,
+ * and add the margin for the tcpiphdr overhead */
+ if (M_FREEROOM(m) < pkt_len + TCPIPHDR_DELTA + 2) {
+ m_inc(m, pkt_len + TCPIPHDR_DELTA + 2);
}
- m->m_len = pkt_len + 2;
- memcpy(m->m_data + 2, pkt, pkt_len);
+ m->m_len = pkt_len + TCPIPHDR_DELTA + 2;
+ memcpy(m->m_data + TCPIPHDR_DELTA + 2, pkt, pkt_len);
- m->m_data += 2 + ETH_HLEN;
- m->m_len -= 2 + ETH_HLEN;
+ m->m_data += TCPIPHDR_DELTA + 2 + ETH_HLEN;
+ m->m_len -= TCPIPHDR_DELTA + 2 + ETH_HLEN;
if (proto == ETH_P_IP) {
ip_input(m);
diff --git a/slirp/socket.c b/slirp/socket.c
index 31bbb7e..567f9bc 100644
--- a/slirp/socket.c
+++ b/slirp/socket.c
@@ -482,7 +482,18 @@ sorecvfrom(struct socket *so)
if (!m) {
return;
}
- m->m_data += IF_MAXLINKHDR;
+ switch (so->so_ffamily) {
+ case AF_INET:
+ m->m_data += IF_MAXLINKHDR + sizeof(struct udpiphdr);
+ break;
+ case AF_INET6:
+ m->m_data += IF_MAXLINKHDR + sizeof(struct ip6)
+ + sizeof(struct udphdr);
+ break;
+ default:
+ assert(0);
+ break;
+ }
/*
* XXX Shouldn't FIONREAD packets destined for port 53,
diff --git a/slirp/tcp_input.c b/slirp/tcp_input.c
index 25929bd..dde89b6 100644
--- a/slirp/tcp_input.c
+++ b/slirp/tcp_input.c
@@ -254,11 +254,6 @@ tcp_input(struct mbuf *m, int iphlen, struct socket *inso)
}
slirp = m->slirp;
- /*
- * Get IP and TCP header together in first mbuf.
- * Note: IP leaves IP header in first mbuf.
- */
- ti = mtod(m, struct tcpiphdr *);
if (iphlen > sizeof(struct ip )) {
ip_stripoptions(m, (struct mbuf *)0);
iphlen=sizeof(struct ip );
@@ -275,14 +270,28 @@ tcp_input(struct mbuf *m, int iphlen, struct socket *inso)
save_ip.ip_len+= iphlen;
/*
+ * Get IP and TCP header together in first mbuf.
+ * Note: IP leaves IP header in first mbuf.
+ */
+ m->m_data -= sizeof(struct tcpiphdr) - (sizeof(struct ip)
+ + sizeof(struct tcphdr));
+ m->m_len += sizeof(struct tcpiphdr) - (sizeof(struct ip)
+ + sizeof(struct tcphdr));
+ ti = mtod(m, struct tcpiphdr *);
+
+ /*
* Checksum extended TCP header and data.
*/
- tlen = ((struct ip *)ti)->ip_len;
- tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
- memset(&ti->ti_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
- ti->ti_x1 = 0;
+ tlen = ip->ip_len;
+ tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
+ memset(&ti->ih_mbuf, 0 , sizeof(struct mbuf_ptr));
+ memset(&ti->ti, 0, sizeof(ti->ti));
+ ti->ti_x0 = 0;
+ ti->ti_src = save_ip.ip_src;
+ ti->ti_dst = save_ip.ip_dst;
+ ti->ti_pr = save_ip.ip_p;
ti->ti_len = htons((uint16_t)tlen);
- len = sizeof(struct ip ) + tlen;
+ len = ((sizeof(struct tcpiphdr) - sizeof(struct tcphdr)) + tlen);
if(cksum(m, len)) {
goto drop;
}
@@ -1466,7 +1475,7 @@ tcp_mss(struct tcpcb *tp, u_int offer)
DEBUG_ARG("tp = %lx", (long)tp);
DEBUG_ARG("offer = %d", offer);
- mss = min(IF_MTU, IF_MRU) - sizeof(struct tcpiphdr);
+ mss = min(IF_MTU, IF_MRU) - sizeof(struct tcphdr) + sizeof(struct ip);
if (offer)
mss = min(mss, offer);
mss = max(mss, 32);
diff --git a/slirp/tcp_output.c b/slirp/tcp_output.c
index 8aa3d90..4726f00 100644
--- a/slirp/tcp_output.c
+++ b/slirp/tcp_output.c
@@ -447,15 +447,23 @@ send:
*/
m->m_len = hdrlen + len; /* XXX Needed? m_len should be correct */
- {
+ struct tcpiphdr tcpiph_save = *(mtod(m, struct tcpiphdr *));
+ m->m_data += sizeof(struct tcpiphdr) - sizeof(struct tcphdr)
+ - sizeof(struct ip);
+ m->m_len -= sizeof(struct tcpiphdr) - sizeof(struct tcphdr)
+ - sizeof(struct ip);
+ struct ip *ip = mtod(m, struct ip *);
- ((struct ip *)ti)->ip_len = m->m_len;
+ ip->ip_len = m->m_len;
+ ip->ip_dst = tcpiph_save.ti_dst;
+ ip->ip_src = tcpiph_save.ti_src;
+ ip->ip_p = tcpiph_save.ti_pr;
- ((struct ip *)ti)->ip_ttl = IPDEFTTL;
- ((struct ip *)ti)->ip_tos = so->so_iptos;
+ ip->ip_ttl = IPDEFTTL;
+ ip->ip_tos = so->so_iptos;
error = ip_output(so, m);
- }
+
if (error) {
out:
return (error);
diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c
index 3558115..b052947 100644
--- a/slirp/tcp_subr.c
+++ b/slirp/tcp_subr.c
@@ -75,9 +75,10 @@ tcp_template(struct tcpcb *tp)
register struct tcpiphdr *n = &tp->t_template;
n->ti_mbuf = NULL;
- n->ti_x1 = 0;
+ memset(&n->ti, 0, sizeof(n->ti));
+ n->ti_x0 = 0;
n->ti_pr = IPPROTO_TCP;
- n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
+ n->ti_len = htons(sizeof(struct tcphdr));
n->ti_src = so->so_faddr;
n->ti_dst = so->so_laddr;
n->ti_sport = so->so_fport;
@@ -130,6 +131,7 @@ tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct
mbuf *m,
m->m_data += IF_MAXLINKHDR;
*mtod(m, struct tcpiphdr *) = *ti;
ti = mtod(m, struct tcpiphdr *);
+ memset(&ti->ti, 0, sizeof(ti->ti));
flags = TH_ACK;
} else {
/*
@@ -149,8 +151,8 @@ tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct
mbuf *m,
tlen += sizeof (struct tcpiphdr);
m->m_len = tlen;
- ti->ti_mbuf = NULL;
- ti->ti_x1 = 0;
+ ti->ti_mbuf = NULL;
+ ti->ti_x0 = 0;
ti->ti_seq = htonl(seq);
ti->ti_ack = htonl(ack);
ti->ti_x2 = 0;
@@ -163,12 +165,23 @@ tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct
mbuf *m,
ti->ti_urp = 0;
ti->ti_sum = 0;
ti->ti_sum = cksum(m, tlen);
- ((struct ip *)ti)->ip_len = tlen;
- if(flags & TH_RST)
- ((struct ip *)ti)->ip_ttl = MAXTTL;
- else
- ((struct ip *)ti)->ip_ttl = IPDEFTTL;
+ struct tcpiphdr tcpiph_save = *(mtod(m, struct tcpiphdr *));
+ m->m_data += sizeof(struct tcpiphdr) - sizeof(struct tcphdr)
+ - sizeof(struct ip);
+ m->m_len -= sizeof(struct tcpiphdr) - sizeof(struct tcphdr)
+ - sizeof(struct ip);
+ struct ip *ip = mtod(m, struct ip *);
+ ip->ip_len = tlen;
+ ip->ip_dst = tcpiph_save.ti_dst;
+ ip->ip_src = tcpiph_save.ti_src;
+ ip->ip_p = tcpiph_save.ti_pr;
+
+ if (flags & TH_RST) {
+ ip->ip_ttl = MAXTTL;
+ } else {
+ ip->ip_ttl = IPDEFTTL;
+ }
(void) ip_output((struct socket *)0, m);
}
diff --git a/slirp/tcpip.h b/slirp/tcpip.h
index 7974ce3..d9b5d70 100644
--- a/slirp/tcpip.h
+++ b/slirp/tcpip.h
@@ -37,15 +37,23 @@
* Tcp+ip header, after ip options removed.
*/
struct tcpiphdr {
- struct ipovly ti_i; /* overlaid ip structure */
- struct tcphdr ti_t; /* tcp header */
+ struct mbuf_ptr ih_mbuf; /* backpointer to mbuf */
+ union {
+ struct {
+ struct in_addr ih_src; /* source internet address */
+ struct in_addr ih_dst; /* destination internet address */
+ uint8_t ih_x1; /* (unused) */
+ uint8_t ih_pr; /* protocol */
+ } ti_i4;
+ } ti;
+ uint16_t ti_x0;
+ uint16_t ti_len; /* protocol length */
+ struct tcphdr ti_t; /* tcp header */
};
-#define ti_mbuf ti_i.ih_mbuf.mptr
-#define ti_x1 ti_i.ih_x1
-#define ti_pr ti_i.ih_pr
-#define ti_len ti_i.ih_len
-#define ti_src ti_i.ih_src
-#define ti_dst ti_i.ih_dst
+#define ti_mbuf ih_mbuf.mptr
+#define ti_pr ti.ti_i4.ih_pr
+#define ti_src ti.ti_i4.ih_src
+#define ti_dst ti.ti_i4.ih_dst
#define ti_sport ti_t.th_sport
#define ti_dport ti_t.th_dport
#define ti_seq ti_t.th_seq
@@ -65,6 +73,13 @@ struct tcpiphdr {
#define tcpfrag_list_end(F, T) (tcpiphdr2qlink(F) == (struct qlink*)(T))
#define tcpfrag_list_empty(T) ((T)->seg_next == (struct tcpiphdr*)(T))
+/* This is the difference between the size of a tcpiphdr structure, and the
+ * size of actual ip+tcp headers, rounded up since we need to align data. */
+#define TCPIPHDR_DELTA\
+ (max(0,\
+ (sizeof(struct tcpiphdr)\
+ - sizeof(struct ip) - sizeof(struct tcphdr) + 3)&~3))
+
/*
* Just a clean way to get to the first byte
* of the packet
--
1.8.4.2
