// SPDX-License-Identifier: GPL-2.0-only
#define KMSG_COMPONENT "IPVS"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/module.h>
#include <linux/kernel.h>
#include <net/ip_vs.h>
#include <net/netfilter/nf_conntrack.h>
#include <linux/netfilter/nf_conntrack_sip.h>
#ifdef CONFIG_IP_VS_DEBUG
static const char *ip_vs_dbg_callid(char *buf, size_t buf_len,
const char *callid, size_t callid_len,
int *idx)
{
size_t max_len = 64;
size_t len = min3(max_len, callid_len, buf_len - *idx - 1);
memcpy(buf + *idx, callid, len);
buf[*idx+len] = '\0';
*idx += len + 1;
return buf + *idx - len;
}
#define IP_VS_DEBUG_CALLID(callid, len) \
ip_vs_dbg_callid(ip_vs_dbg_buf, sizeof(ip_vs_dbg_buf), \
callid, len, &ip_vs_dbg_idx)
#endif
static int get_callid(const char *dptr, unsigned int dataoff,
unsigned int datalen,
unsigned int *matchoff, unsigned int *matchlen)
{
/* Find callid */
while (1) {
int ret = ct_sip_get_header(NULL, dptr, dataoff, datalen,
SIP_HDR_CALL_ID, matchoff,
matchlen);
if (ret > 0)
break;
if (!ret)
return -EINVAL;
dataoff += *matchoff;
}
/* Too large is useless */
if (*matchlen > IP_VS_PEDATA_MAXLEN)
return -EINVAL;
/* SIP headers are always followed by a line terminator */
if (*matchoff + *matchlen == datalen)
return -EINVAL;
/* RFC 2543 allows lines to be terminated with CR, LF or CRLF,
* RFC 3261 allows only CRLF, we support both. */
if (*(dptr + *matchoff + *matchlen) != '\r' &&
*(dptr + *matchoff + *matchlen) != '\n')
return -EINVAL;
IP_VS_DBG_BUF(9, "SIP callid %s (%d bytes)\n",
IP_VS_DEBUG_CALLID(dptr + *matchoff, *matchlen),
*matchlen);
return 0;
}
static int
ip_vs_sip_fill_param(struct ip_vs_conn_param *p, struct sk_buff *skb)
{
struct ip_vs_iphdr iph;
unsigned int dataoff, datalen, matchoff, matchlen;
const char *dptr;
int retc;
retc = ip_vs_fill_iph_skb(p->af, skb, false, &iph);
/* Only useful with UDP */
if (!retc || iph.protocol != IPPROTO_UDP)
return -EINVAL;
/* todo: IPv6 fragments:
* I think this only should be done for the first fragment. /HS
*/
dataoff = iph.len + sizeof(struct udphdr);
if (dataoff >= skb->len)
return -EINVAL;
retc = skb_linearize(skb);
if (retc < 0)
return retc;
dptr = skb->data + dataoff;
datalen = skb->len - dataoff;
if (get_callid(dptr, 0, datalen, &matchoff, &matchlen))
return -EINVAL;
/* N.B: pe_data is only set on success,
* this allows fallback to the default persistence logic on failure
*/
p->pe_data = kmemdup(dptr + matchoff, matchlen, GFP_ATOMIC);
if (!p->pe_data)
return -ENOMEM;
p->pe_data_len = matchlen;
return 0;
}
static bool ip_vs_sip_ct_match(const struct ip_vs_conn_param *p,
struct ip_vs_conn *ct)
{
bool ret = false;
if (ct->af == p->af &&
ip_vs_addr_equal(p->af, p->caddr, &ct->caddr) &&
/* protocol should only be IPPROTO_IP if
* d_addr is a fwmark */
ip_vs_addr_equal(p->protocol == IPPROTO_IP ? AF_UNSPEC : p->af,
p->vaddr, &ct->vaddr) &&
ct->vport == p->vport &&
ct->flags & IP_VS_CONN_F_TEMPLATE &&
ct->protocol == p->protocol &&
ct->pe_data && ct->pe_data_len == p->pe_data_len &&
!memcmp(ct->pe_data, p->pe_data, p->pe_data_len))
ret = true;
IP_VS_DBG_BUF(9, "SIP template match %s %s->%s:%d %s\n",
ip_vs_proto_name(p->protocol),
IP_VS_DEBUG_CALLID(p->pe_data, p->pe_data_len),
IP_VS_DBG_ADDR(p->af, p->vaddr), ntohs(p->vport),
ret ? "hit" : "not hit");
return ret;
}
static u32 ip_vs_sip_hashkey_raw(const struct ip_vs_conn_param *p,
u32 initval, bool inverse)
{
return jhash(p->pe_data, p->pe_data_len, initval);
}
static int ip_vs_sip_show_pe_data(const struct ip_vs_conn *cp, char *buf)
{
memcpy(buf, cp->pe_data, cp->pe_data_len);
return cp->pe_data_len;
}
static struct ip_vs_conn *
ip_vs_sip_conn_out(struct ip_vs_service *svc,
struct ip_vs_dest *dest,
struct sk_buff *skb,
const struct ip_vs_iphdr *iph,
__be16 dport,
__be16 cport)
{
if (likely(iph->protocol == IPPROTO_UDP))
return ip_vs_new_conn_out(svc, dest, skb, iph, dport, cport);
/* currently no need to handle other than UDP */
return NULL;
}
static struct ip_vs_pe ip_vs_sip_pe =
{
.name = "sip",
.refcnt = ATOMIC_INIT(0),
.module = THIS_MODULE,
.n_list = LIST_HEAD_INIT(ip_vs_sip_pe.n_list),
.fill_param = ip_vs_sip_fill_param,
.ct_match = ip_vs_sip_ct_match,
.hashkey_raw = ip_vs_sip_hashkey_raw,
.show_pe_data = ip_vs_sip_show_pe_data,
.conn_out = ip_vs_sip_conn_out,
};
static int __init ip_vs_sip_init(void)
{
return register_ip_vs_pe(&ip_vs_sip_pe);
}
static void __exit ip_vs_sip_cleanup(void)
{
unregister_ip_vs_pe(&ip_vs_sip_pe);
synchronize_rcu();
}
module_init(ip_vs_sip_init);
module_exit(ip_vs_sip_cleanup);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ipvs sip helper");
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