Re: [lwip-users] 2 Devices

[Joel Cunningham]

On 11/10/2017 03:51 AM, Fabian Cenedese wrote:
> struct sockaddr_in addr;
> s=socket(AF_INET, SOCK_DGRAM, 0);
> if (s >= 0) {
>          // set up port from any address to bind to
>          memset(&addr, 0, sizeof(addr));
>          addr.sin_len=sizeof(addr);
>          addr.sin_family=AF_INET;
>          addr.sin_port=PP_HTONS(port);
>          addr.sin_addr.s_addr=PP_HTONL(INADDR_ANY);
>          // connect
>          int ret = bind(s, (struct sockaddr*)&addr, sizeof(addr));
>          // should succeed
>          if (ret < 0) {
>                  // error
>          }
>          else {
>                  // limit to one interface
>                  struct ifreq ifr;
>                  memset(&ifr, 0, sizeof(struct ifreq));
>                  ifr.ifr_name[0] = 'e';// IFNAME0;
>                  ifr.ifr_name[1] = '0';// IFNAME1

Unless you've made modifications to LwIP's interface naming/numbering, 
the name is at least least 3 characters: two chars and a number (which 
is also the index).  See netif_find(), which is invoked from 
SO_BINDTODEVICE.
>                  int rc = setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE,
>                                  (void*)&ifr, sizeof(struct ifreq));
>          }
> }
Joel