From 7df4c681678612d196b4e1eec24963d181fdb28a Mon Sep 17 00:00:00 2001
From: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Date: Sun, 5 Apr 2020 17:18:23 +0100
Subject: [PATCH] drop runtime old kernel support

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
---
 src/dnsmasq.c |  4 ----
 src/dnsmasq.h |  5 +---
 src/ipset.c   | 64 ++++-----------------------------------------------
 src/netlink.c |  3 +--
 src/util.c    | 19 ---------------
 5 files changed, 6 insertions(+), 89 deletions(-)

--- a/src/dnsmasq.c
+++ b/src/dnsmasq.c
@@ -95,10 +95,6 @@ int main (int argc, char **argv)
   
   read_opts(argc, argv, compile_opts);
  
-#ifdef HAVE_LINUX_NETWORK
-  daemon->kernel_version = kernel_version();
-#endif
-
   if (daemon->edns_pktsz < PACKETSZ)
     daemon->edns_pktsz = PACKETSZ;
 
--- a/src/dnsmasq.h
+++ b/src/dnsmasq.h
@@ -1112,7 +1112,7 @@ extern struct daemon {
   int inotifyfd;
 #endif
 #if defined(HAVE_LINUX_NETWORK)
-  int netlinkfd, kernel_version;
+  int netlinkfd;
 #elif defined(HAVE_BSD_NETWORK)
   int dhcp_raw_fd, dhcp_icmp_fd, routefd;
 #endif
@@ -1292,9 +1292,6 @@ int read_write(int fd, unsigned char *pa
 void close_fds(long max_fd, int spare1, int spare2, int spare3);
 int wildcard_match(const char* wildcard, const char* match);
 int wildcard_matchn(const char* wildcard, const char* match, int num);
-#ifdef HAVE_LINUX_NETWORK
-int kernel_version(void);
-#endif
 
 /* log.c */
 void die(char *message, char *arg1, int exit_code) ATTRIBUTE_NORETURN;
--- a/src/ipset.c
+++ b/src/ipset.c
@@ -70,7 +70,7 @@ struct my_nfgenmsg {
 
 #define NL_ALIGN(len) (((len)+3) & ~(3))
 static const struct sockaddr_nl snl = { .nl_family = AF_NETLINK };
-static int ipset_sock, old_kernel;
+static int ipset_sock;
 static char *buffer;
 
 static inline void add_attr(struct nlmsghdr *nlh, uint16_t type, size_t len, const void *data)
@@ -85,12 +85,7 @@ static inline void add_attr(struct nlmsg
 
 void ipset_init(void)
 {
-  old_kernel = (daemon->kernel_version < KERNEL_VERSION(2,6,32));
-  
-  if (old_kernel && (ipset_sock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) != -1)
-    return;
-  
-  if (!old_kernel && 
+  if (
       (buffer = safe_malloc(BUFF_SZ)) &&
       (ipset_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER)) != -1 &&
       (bind(ipset_sock, (struct sockaddr *)&snl, sizeof(snl)) != -1))
@@ -147,65 +142,14 @@ static int new_add_to_ipset(const char *
   return errno == 0 ? 0 : -1;
 }
 
-
-static int old_add_to_ipset(const char *setname, const union all_addr *ipaddr, int remove)
-{
-  socklen_t size;
-  struct ip_set_req_adt_get {
-    unsigned op;
-    unsigned version;
-    union {
-      char name[IPSET_MAXNAMELEN];
-      uint16_t index;
-    } set;
-    char typename[IPSET_MAXNAMELEN];
-  } req_adt_get;
-  struct ip_set_req_adt {
-    unsigned op;
-    uint16_t index;
-    uint32_t ip;
-  } req_adt;
-  
-  if (strlen(setname) >= sizeof(req_adt_get.set.name)) 
-    {
-      errno = ENAMETOOLONG;
-      return -1;
-    }
-  
-  req_adt_get.op = 0x10;
-  req_adt_get.version = 3;
-  strcpy(req_adt_get.set.name, setname);
-  size = sizeof(req_adt_get);
-  if (getsockopt(ipset_sock, SOL_IP, 83, &req_adt_get, &size) < 0)
-    return -1;
-  req_adt.op = remove ? 0x102 : 0x101;
-  req_adt.index = req_adt_get.set.index;
-  req_adt.ip = ntohl(ipaddr->addr4.s_addr);
-  if (setsockopt(ipset_sock, SOL_IP, 83, &req_adt, sizeof(req_adt)) < 0)
-    return -1;
-  
-  return 0;
-}
-
-
-
 int add_to_ipset(const char *setname, const union all_addr *ipaddr, int flags, int remove)
 {
   int ret = 0, af = AF_INET;
 
   if (flags & F_IPV6)
-    {
       af = AF_INET6;
-      /* old method only supports IPv4 */
-      if (old_kernel)
-	{
-	  errno = EAFNOSUPPORT ;
-	  ret = -1;
-	}
-    }
-  
-  if (ret != -1) 
-    ret = old_kernel ? old_add_to_ipset(setname, ipaddr, remove) : new_add_to_ipset(setname, ipaddr, af, remove);
+
+  ret = new_add_to_ipset(setname, ipaddr, af, remove);
 
   if (ret == -1)
      my_syslog(LOG_ERR, _("failed to update ipset %s: %s"), setname, strerror(errno));
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -92,8 +92,7 @@ char *netlink_init(void)
   iov.iov_len = 100;
   iov.iov_base = safe_malloc(iov.iov_len);
   
-  if (daemon->kernel_version >= KERNEL_VERSION(2,6,30) &&
-      setsockopt(daemon->netlinkfd, SOL_NETLINK, NETLINK_NO_ENOBUFS, &opt, sizeof(opt)) == -1)
+  if (setsockopt(daemon->netlinkfd, SOL_NETLINK, NETLINK_NO_ENOBUFS, &opt, sizeof(opt)) == -1)
     return _("warning: failed to set NETLINK_NO_ENOBUFS on netlink socket");
   
   return NULL;
--- a/src/util.c
+++ b/src/util.c
@@ -786,22 +786,3 @@ int wildcard_matchn(const char* wildcard
 
   return (!num) || (*wildcard == *match);
 }
-
-#ifdef HAVE_LINUX_NETWORK
-int kernel_version(void)
-{
-  struct utsname utsname;
-  int version;
-  char *split;
-  
-  if (uname(&utsname) < 0)
-    die(_("failed to find kernel version: %s"), NULL, EC_MISC);
-  
-  split = strtok(utsname.release, ".");
-  version = (split ? atoi(split) : 0);
-  split = strtok(NULL, ".");
-  version = version * 256 + (split ? atoi(split) : 0);
-  split = strtok(NULL, ".");
-  return version * 256 + (split ? atoi(split) : 0);
-}
-#endif