From: Hannes Eder Use nf_conntrack/nf_nat code to do the packet mangling and the TCP sequence adjusting. The function 'ip_vs_skb_replace' is now dead code, so it is removed. To SNAT FTP, use something like: % iptables -t nat -A POSTROUTING -m ipvs --vaddr 192.168.100.30/32 \ > --vport 21 -j SNAT --to-source 192.168.10.10 and for the data connections in passive mode: % iptables -t nat -A POSTROUTING -m ipvs --vaddr 192.168.100.30/32 \ > --vportctl 21 -j SNAT --to-source 192.168.10.10 using '-m state --state RELATED' would also works. Make sure the kernel modules ip_vs_ftp, nf_conntrack_ftp, and nf_nat_ftp are loaded. [ up-port and minor fixes by Simon Horman ] Signed-off-by: Hannes Eder Signed-off-by: Simon Horman --- include/net/ip_vs.h | 2 net/netfilter/ipvs/Kconfig | 2 net/netfilter/ipvs/ip_vs_app.c | 43 --------- net/netfilter/ipvs/ip_vs_core.c | 1 net/netfilter/ipvs/ip_vs_ftp.c | 174 ++++++++++++++++++++++++++++++++++++--- 5 files changed, 164 insertions(+), 58 deletions(-) v2.6 * pointer arguments for %pI4 v2.5 * Use nf_ct_is_untracked(ct) instead of nf_ct_is_untracked(), the latter is blatantly incorrect * Return 0 (and thus drop the packet) if mangling wasn't attempted v2.4 As suggested by Patrick McHardy * Use nf_conntrack_untracked() instead of &nf_conntrack_untracked * Fix ip_vs_ftp_out logic - Don't call nf_nat_mangle_tcp_packet() unless ct is valid and tracked - Only call ip_vs_expect_relatedi() if nf_nat_mangle_tcp_packet() succeeds - Note that packets are dropped if mangling fails Other * Drop unrelated cosmetic change to sizing of buf in ip_vs_ftp_out() v2.3 * Up-port * Drop buf_len = snprintf() change - its a separate, cosmetic, fix As suggested by Patrick McHardy * Use %pI4 instead of NIPQUAD v2.2 * No change v2.1 * Up-port Index: nf-next-2.6/include/net/ip_vs.h =================================================================== --- nf-next-2.6.orig/include/net/ip_vs.h 2010-07-11 17:30:19.000000000 +0900 +++ nf-next-2.6/include/net/ip_vs.h 2010-07-11 17:33:33.000000000 +0900 @@ -736,8 +736,6 @@ extern void ip_vs_app_inc_put(struct ip_ extern int ip_vs_app_pkt_out(struct ip_vs_conn *, struct sk_buff *skb); extern int ip_vs_app_pkt_in(struct ip_vs_conn *, struct sk_buff *skb); -extern int ip_vs_skb_replace(struct sk_buff *skb, gfp_t pri, - char *o_buf, int o_len, char *n_buf, int n_len); extern int ip_vs_app_init(void); extern void ip_vs_app_cleanup(void); Index: nf-next-2.6/net/netfilter/ipvs/Kconfig =================================================================== --- nf-next-2.6.orig/net/netfilter/ipvs/Kconfig 2010-07-11 17:33:06.000000000 +0900 +++ nf-next-2.6/net/netfilter/ipvs/Kconfig 2010-07-11 17:33:33.000000000 +0900 @@ -235,7 +235,7 @@ comment 'IPVS application helper' config IP_VS_FTP tristate "FTP protocol helper" - depends on IP_VS_PROTO_TCP + depends on IP_VS_PROTO_TCP && NF_NAT ---help--- FTP is a protocol that transfers IP address and/or port number in the payload. In the virtual server via Network Address Translation, Index: nf-next-2.6/net/netfilter/ipvs/ip_vs_app.c =================================================================== --- nf-next-2.6.orig/net/netfilter/ipvs/ip_vs_app.c 2010-07-11 17:30:19.000000000 +0900 +++ nf-next-2.6/net/netfilter/ipvs/ip_vs_app.c 2010-07-11 17:33:33.000000000 +0900 @@ -569,49 +569,6 @@ static const struct file_operations ip_v }; #endif - -/* - * Replace a segment of data with a new segment - */ -int ip_vs_skb_replace(struct sk_buff *skb, gfp_t pri, - char *o_buf, int o_len, char *n_buf, int n_len) -{ - int diff; - int o_offset; - int o_left; - - EnterFunction(9); - - diff = n_len - o_len; - o_offset = o_buf - (char *)skb->data; - /* The length of left data after o_buf+o_len in the skb data */ - o_left = skb->len - (o_offset + o_len); - - if (diff <= 0) { - memmove(o_buf + n_len, o_buf + o_len, o_left); - memcpy(o_buf, n_buf, n_len); - skb_trim(skb, skb->len + diff); - } else if (diff <= skb_tailroom(skb)) { - skb_put(skb, diff); - memmove(o_buf + n_len, o_buf + o_len, o_left); - memcpy(o_buf, n_buf, n_len); - } else { - if (pskb_expand_head(skb, skb_headroom(skb), diff, pri)) - return -ENOMEM; - skb_put(skb, diff); - memmove(skb->data + o_offset + n_len, - skb->data + o_offset + o_len, o_left); - skb_copy_to_linear_data_offset(skb, o_offset, n_buf, n_len); - } - - /* must update the iph total length here */ - ip_hdr(skb)->tot_len = htons(skb->len); - - LeaveFunction(9); - return 0; -} - - int __init ip_vs_app_init(void) { /* we will replace it with proc_net_ipvs_create() soon */ Index: nf-next-2.6/net/netfilter/ipvs/ip_vs_core.c =================================================================== --- nf-next-2.6.orig/net/netfilter/ipvs/ip_vs_core.c 2010-07-11 17:33:06.000000000 +0900 +++ nf-next-2.6/net/netfilter/ipvs/ip_vs_core.c 2010-07-11 17:33:33.000000000 +0900 @@ -54,7 +54,6 @@ EXPORT_SYMBOL(register_ip_vs_scheduler); EXPORT_SYMBOL(unregister_ip_vs_scheduler); -EXPORT_SYMBOL(ip_vs_skb_replace); EXPORT_SYMBOL(ip_vs_proto_name); EXPORT_SYMBOL(ip_vs_conn_new); EXPORT_SYMBOL(ip_vs_conn_in_get); Index: nf-next-2.6/net/netfilter/ipvs/ip_vs_ftp.c =================================================================== --- nf-next-2.6.orig/net/netfilter/ipvs/ip_vs_ftp.c 2010-07-11 17:30:19.000000000 +0900 +++ nf-next-2.6/net/netfilter/ipvs/ip_vs_ftp.c 2010-07-11 18:01:58.000000000 +0900 @@ -20,6 +20,17 @@ * * Author: Wouter Gadeyne * + * + * Code for ip_vs_expect_related and ip_vs_expect_callback is taken from + * http://www.ssi.bg/~ja/nfct/: + * + * ip_vs_nfct.c: Netfilter connection tracking support for IPVS + * + * Portions Copyright (C) 2001-2002 + * Antefacto Ltd, 181 Parnell St, Dublin 1, Ireland. + * + * Portions Copyright (C) 2003-2008 + * Julian Anastasov */ #define KMSG_COMPONENT "IPVS" @@ -32,6 +43,9 @@ #include #include #include +#include +#include +#include #include #include #include @@ -43,6 +57,16 @@ #define SERVER_STRING "227 Entering Passive Mode (" #define CLIENT_STRING "PORT " +#define FMT_TUPLE "%pI4:%u->%pI4:%u/%u" +#define ARG_TUPLE(T) &(T)->src.u3.ip, ntohs((T)->src.u.all), \ + &(T)->dst.u3.ip, ntohs((T)->dst.u.all), \ + (T)->dst.protonum + +#define FMT_CONN "%pI4:%u->%pI4:%u->%pI4:%u/%u:%u" +#define ARG_CONN(C) &((C)->caddr.ip), ntohs((C)->cport), \ + &((C)->vaddr.ip), ntohs((C)->vport), \ + &((C)->daddr.ip), ntohs((C)->dport), \ + (C)->protocol, (C)->state /* * List of ports (up to IP_VS_APP_MAX_PORTS) to be handled by helper @@ -123,6 +147,119 @@ static int ip_vs_ftp_get_addrport(char * return 1; } +/* + * Called from init_conntrack() as expectfn handler. + */ +static void +ip_vs_expect_callback(struct nf_conn *ct, + struct nf_conntrack_expect *exp) +{ + struct nf_conntrack_tuple *orig, new_reply; + struct ip_vs_conn *cp; + + if (exp->tuple.src.l3num != PF_INET) + return; + + /* + * We assume that no NF locks are held before this callback. + * ip_vs_conn_out_get and ip_vs_conn_in_get should match their + * expectations even if they use wildcard values, now we provide the + * actual values from the newly created original conntrack direction. + * The conntrack is confirmed when packet reaches IPVS hooks. + */ + + /* RS->CLIENT */ + orig = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; + cp = ip_vs_conn_out_get(exp->tuple.src.l3num, orig->dst.protonum, + &orig->src.u3, orig->src.u.tcp.port, + &orig->dst.u3, orig->dst.u.tcp.port); + if (cp) { + /* Change reply CLIENT->RS to CLIENT->VS */ + new_reply = ct->tuplehash[IP_CT_DIR_REPLY].tuple; + IP_VS_DBG(7, "%s(): ct=%p, status=0x%lX, tuples=" FMT_TUPLE ", " + FMT_TUPLE ", found inout cp=" FMT_CONN "\n", + __func__, ct, ct->status, + ARG_TUPLE(orig), ARG_TUPLE(&new_reply), + ARG_CONN(cp)); + new_reply.dst.u3 = cp->vaddr; + new_reply.dst.u.tcp.port = cp->vport; + IP_VS_DBG(7, "%s(): ct=%p, new tuples=" FMT_TUPLE ", " FMT_TUPLE + ", inout cp=" FMT_CONN "\n", + __func__, ct, + ARG_TUPLE(orig), ARG_TUPLE(&new_reply), + ARG_CONN(cp)); + goto alter; + } + + /* CLIENT->VS */ + cp = ip_vs_conn_in_get(exp->tuple.src.l3num, orig->dst.protonum, + &orig->src.u3, orig->src.u.tcp.port, + &orig->dst.u3, orig->dst.u.tcp.port); + if (cp) { + /* Change reply VS->CLIENT to RS->CLIENT */ + new_reply = ct->tuplehash[IP_CT_DIR_REPLY].tuple; + IP_VS_DBG(7, "%s(): ct=%p, status=0x%lX, tuples=" FMT_TUPLE ", " + FMT_TUPLE ", found outin cp=" FMT_CONN "\n", + __func__, ct, ct->status, + ARG_TUPLE(orig), ARG_TUPLE(&new_reply), + ARG_CONN(cp)); + new_reply.src.u3 = cp->daddr; + new_reply.src.u.tcp.port = cp->dport; + IP_VS_DBG(7, "%s(): ct=%p, new tuples=" FMT_TUPLE ", " + FMT_TUPLE ", outin cp=" FMT_CONN "\n", + __func__, ct, + ARG_TUPLE(orig), ARG_TUPLE(&new_reply), + ARG_CONN(cp)); + goto alter; + } + + IP_VS_DBG(7, "%s(): ct=%p, status=0x%lX, tuple=" FMT_TUPLE + " - unknown expect\n", + __func__, ct, ct->status, ARG_TUPLE(orig)); + return; + +alter: + /* Never alter conntrack for non-NAT conns */ + if (IP_VS_FWD_METHOD(cp) == IP_VS_CONN_F_MASQ) + nf_conntrack_alter_reply(ct, &new_reply); + ip_vs_conn_put(cp); + return; +} + +/* + * Create NF conntrack expectation with wildcard (optional) source port. + * Then the default callback function will alter the reply and will confirm + * the conntrack entry when the first packet comes. + */ +static void +ip_vs_expect_related(struct sk_buff *skb, struct nf_conn *ct, + struct ip_vs_conn *cp, u_int8_t proto, + const __be16 *port, int from_rs) +{ + struct nf_conntrack_expect *exp; + + BUG_ON(!ct || ct == &nf_conntrack_untracked); + + exp = nf_ct_expect_alloc(ct); + if (!exp) + return; + + if (from_rs) + nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, + nf_ct_l3num(ct), &cp->daddr, &cp->caddr, + proto, port, &cp->cport); + else + nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, + nf_ct_l3num(ct), &cp->caddr, &cp->vaddr, + proto, port, &cp->vport); + + exp->expectfn = ip_vs_expect_callback; + + IP_VS_DBG(7, "%s(): ct=%p, expect tuple=" FMT_TUPLE "\n", + __func__, ct, ARG_TUPLE(&exp->tuple)); + nf_ct_expect_related(exp); + nf_ct_expect_put(exp); +} /* * Look at outgoing ftp packets to catch the response to a PASV command @@ -149,7 +286,9 @@ static int ip_vs_ftp_out(struct ip_vs_ap struct ip_vs_conn *n_cp; char buf[24]; /* xxx.xxx.xxx.xxx,ppp,ppp\000 */ unsigned buf_len; - int ret; + int ret = 0; + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; #ifdef CONFIG_IP_VS_IPV6 /* This application helper doesn't work with IPv6 yet, @@ -219,19 +358,26 @@ static int ip_vs_ftp_out(struct ip_vs_ap buf_len = strlen(buf); + ct = nf_ct_get(skb, &ctinfo); + if (ct && !nf_ct_is_untracked(ct)) { + /* If mangling fails this function will return 0 + * which will cause the packet to be dropped. + * Mangling can only fail under memory pressure, + * hopefully it will succeed on the retransmitted + * packet. + */ + ret = nf_nat_mangle_tcp_packet(skb, ct, ctinfo, + start-data, end-start, + buf, buf_len); + if (ret) + ip_vs_expect_related(skb, ct, n_cp, + IPPROTO_TCP, NULL, 0); + } + /* - * Calculate required delta-offset to keep TCP happy + * Not setting 'diff' is intentional, otherwise the sequence + * would be adjusted twice. */ - *diff = buf_len - (end-start); - - if (*diff == 0) { - /* simply replace it with new passive address */ - memcpy(start, buf, buf_len); - ret = 1; - } else { - ret = !ip_vs_skb_replace(skb, GFP_ATOMIC, start, - end-start, buf, buf_len); - } cp->app_data = NULL; ip_vs_tcp_conn_listen(n_cp); @@ -263,6 +409,7 @@ static int ip_vs_ftp_in(struct ip_vs_app union nf_inet_addr to; __be16 port; struct ip_vs_conn *n_cp; + struct nf_conn *ct; #ifdef CONFIG_IP_VS_IPV6 /* This application helper doesn't work with IPv6 yet, @@ -349,6 +496,11 @@ static int ip_vs_ftp_in(struct ip_vs_app ip_vs_control_add(n_cp, cp); } + ct = (struct nf_conn *)skb->nfct; + if (ct && ct != &nf_conntrack_untracked) + ip_vs_expect_related(skb, ct, n_cp, + IPPROTO_TCP, &n_cp->dport, 1); + /* * Move tunnel to listen state */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/