inet: constify ip headers and in6_addr

Add const qualifiers to structs iphdr, ipv6hdr and in6_addr pointers
where possible, to make code intention more obvious.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 14 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index da5941f18c3c..24efd353279a 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -462,7 +462,7 @@ static void ipgre_err(struct sk_buff *skb, u32 info)
    by themself???
  */
 
-        struct iphdr *iph = (struct iphdr *)skb->data;
+        const struct iphdr *iph = (const struct iphdr *)skb->data;
         __be16       *p = (__be16*)(skb->data+(iph->ihl<<2));
         int grehlen = (iph->ihl<<2) + 4;
         const int type = icmp_hdr(skb)->type;
@@ -534,7 +534,7 @@ out:
         rcu_read_unlock();
 }
 
-static inline void ipgre_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
+static inline void ipgre_ecn_decapsulate(const struct iphdr *iph, struct sk_buff *skb)
 {
         if (INET_ECN_is_ce(iph->tos)) {
                 if (skb->protocol == htons(ETH_P_IP)) {
@@ -546,19 +546,19 @@ static inline void ipgre_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
 }
 
 static inline u8
-ipgre_ecn_encapsulate(u8 tos, struct iphdr *old_iph, struct sk_buff *skb)
+ipgre_ecn_encapsulate(u8 tos, const struct iphdr *old_iph, struct sk_buff *skb)
 {
         u8 inner = 0;
         if (skb->protocol == htons(ETH_P_IP))
                 inner = old_iph->tos;
         else if (skb->protocol == htons(ETH_P_IPV6))
-                inner = ipv6_get_dsfield((struct ipv6hdr *)old_iph);
+                inner = ipv6_get_dsfield((const struct ipv6hdr *)old_iph);
         return INET_ECN_encapsulate(tos, inner);
 }
 
 static int ipgre_rcv(struct sk_buff *skb)
 {
-        struct iphdr *iph;
+        const struct iphdr *iph;
         u8     *h;
         __be16    flags;
         __sum16   csum = 0;
@@ -697,8 +697,8 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
 {
         struct ip_tunnel *tunnel = netdev_priv(dev);
         struct pcpu_tstats *tstats;
-        struct iphdr  *old_iph = ip_hdr(skb);
-        struct iphdr  *tiph;
+        const struct iphdr  *old_iph = ip_hdr(skb);
+        const struct iphdr  *tiph;
         u8     tos;
         __be16 df;
         struct rtable *rt;                      /* Route to the other host */
@@ -714,7 +714,7 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
 
         if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
                 gre_hlen = 0;
-                tiph = (struct iphdr *)skb->data;
+                tiph = (const struct iphdr *)skb->data;
         } else {
                 gre_hlen = tunnel->hlen;
                 tiph = &tunnel->parms.iph;
@@ -735,14 +735,14 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
                 }
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
                 else if (skb->protocol == htons(ETH_P_IPV6)) {
-                        struct in6_addr *addr6;
+                        const struct in6_addr *addr6;
                         int addr_type;
                         struct neighbour *neigh = skb_dst(skb)->neighbour;
 
                         if (neigh == NULL)
                                 goto tx_error;
 
-                        addr6 = (struct in6_addr *)&neigh->primary_key;
+                        addr6 = (const struct in6_addr *)&neigh->primary_key;
                         addr_type = ipv6_addr_type(addr6);
 
                         if (addr_type == IPV6_ADDR_ANY) {
@@ -766,7 +766,7 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
                 if (skb->protocol == htons(ETH_P_IP))
                         tos = old_iph->tos;
                 else if (skb->protocol == htons(ETH_P_IPV6))
-                        tos = ipv6_get_dsfield((struct ipv6hdr *)old_iph);
+                        tos = ipv6_get_dsfield((const struct ipv6hdr *)old_iph);
         }
 
         rt = ip_route_output_gre(dev_net(dev), dst, tiph->saddr,
@@ -881,7 +881,7 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
                         iph->ttl = old_iph->ttl;
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
                 else if (skb->protocol == htons(ETH_P_IPV6))
-                        iph->ttl = ((struct ipv6hdr *)old_iph)->hop_limit;
+                        iph->ttl = ((const struct ipv6hdr *)old_iph)->hop_limit;
 #endif
                 else
                         iph->ttl = ip4_dst_hoplimit(&rt->dst);
@@ -927,7 +927,7 @@ static int ipgre_tunnel_bind_dev(struct net_device *dev)
 {
         struct net_device *tdev = NULL;
         struct ip_tunnel *tunnel;
-        struct iphdr *iph;
+        const struct iphdr *iph;
         int hlen = LL_MAX_HEADER;
         int mtu = ETH_DATA_LEN;
         int addend = sizeof(struct iphdr) + 4;
@@ -1180,7 +1180,7 @@ static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
 
 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr)
 {
-        struct iphdr *iph = (struct iphdr *) skb_mac_header(skb);
+        const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb);
         memcpy(haddr, &iph->saddr, 4);
         return 4;
 }