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