Hello,
Just to make sure: we have not received comments on this patch.
(that said, it's the most complex part of the series, so I'm not
surprised if it takes more time :) )
Samuel
Samuel Thibault, on Sun 14 Feb 2016 18:47:38 +0100, wrote:
> From: Guillaume Subiron <maet...@subiron.org>
>
> 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 c959758..f081c69 100644
> --- a/slirp/mbuf.c
> +++ b/slirp/mbuf.c
> @@ -24,7 +24,8 @@
> * 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 5f42ada..c2c4597 100644
> --- a/slirp/slirp.c
> +++ b/slirp/slirp.c
> @@ -754,15 +754,16 @@ 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 b79ddec..d4b02c8 100644
> --- a/slirp/socket.c
> +++ b/slirp/socket.c
> @@ -483,7 +483,18 @@ 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:
> + g_assert_not_reached();
> + break;
> + }
>
> /*
> * XXX Shouldn't FIONREAD packets destined for port 53,
> diff --git a/slirp/tcp_input.c b/slirp/tcp_input.c
> index 5f845da..26b0c8b 100644
> --- a/slirp/tcp_input.c
> +++ b/slirp/tcp_input.c
> @@ -256,11 +256,6 @@ 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 );
> @@ -277,14 +272,28 @@ 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;
> }
> @@ -1475,7 +1484,7 @@ tcp_mss(struct tcpcb *tp, u_int offer)
> DEBUG_ARG("tp = %p", 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 34e4d2e..7fc6a87 100644
> --- a/slirp/tcp_output.c
> +++ b/slirp/tcp_output.c
> @@ -448,15 +448,23 @@ 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 b1aa1f2..cd021df 100644
> --- a/slirp/tcp_subr.c
> +++ b/slirp/tcp_subr.c
> @@ -76,9 +76,10 @@ 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;
> @@ -131,6 +132,7 @@ 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 {
> /*
> @@ -150,8 +152,8 @@ 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;
> @@ -164,12 +166,23 @@ 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..3c5d127 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
> --
> 2.7.0
>
>
--
Samuel
> X..., c'est un millefeuille avec une couche de crème patissière, une
> de sauce tomate et une de crème d'anchois... Mais c'est vrai que
> c'est un système ouvert: tu peux y rajouter des pépites de chocolat...
-+- Ol in Guide du linuxien pervers - "Remettez m'en une couche !" -+-
