#include <string.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
+#include <unistd.h>
+#include <semaphore.h>
#include <rdma/rdma_cma.h>
#include <rdma/rdma_verbs.h>
int (*getsockopt)(int socket, int level, int optname,
void *optval, socklen_t *optlen);
int (*fcntl)(int socket, int cmd, ... /* arg */);
+ pid_t (*fork)(void);
};
static struct socket_calls real;
static int sq_size;
static int rq_size;
static int sq_inline;
+static int fork_support;
+static int last_accept = -1;
enum fd_type {
fd_normal,
- fd_rsocket
+ fd_rsocket,
+ fd_fork
};
struct fd_info {
var = getenv("RS_INLINE");
if (var)
sq_inline = atoi(var);
+
+ var = getenv("RDMAV_FORK_SAFE");
+ if (var)
+ fork_support = atoi(var);
}
static void init_preload(void)
real.setsockopt = dlsym(RTLD_NEXT, "setsockopt");
real.getsockopt = dlsym(RTLD_NEXT, "getsockopt");
real.fcntl = dlsym(RTLD_NEXT, "fcntl");
+ real.fork = dlsym(RTLD_NEXT, "fork");
rs.socket = dlsym(RTLD_DEFAULT, "rsocket");
rs.bind = dlsym(RTLD_DEFAULT, "rbind");
ret = rsocket(domain, type, protocol);
recursive = 0;
if (ret >= 0) {
- fd_store(index, ret, fd_rsocket);
- set_rsocket_options(ret);
+ if (fork_support) {
+ rclose(ret);
+ ret = real.socket(domain, type, protocol);
+ if (ret < 0)
+ return ret;
+ fd_store(index, ret, fd_fork);
+ } else {
+ fd_store(index, ret, fd_rsocket);
+ set_rsocket_options(ret);
+ }
return index;
}
fd_close(index, &ret);
}
fd_store(index, ret, fd_rsocket);
+ last_accept = index;
return index;
} else {
+ last_accept = -1;
return real.accept(fd, addr, addrlen);
}
}
+static int connect_fork(int socket, const struct sockaddr *addr, socklen_t addrlen)
+{
+ int fd, ret;
+ uint32_t msg;
+
+ fd = fd_getd(socket);
+ ret = real.connect(fd, addr, addrlen);
+ if (ret)
+ return ret;
+
+ ret = real.read(fd, &msg, sizeof msg);
+ if ((ret != sizeof msg) || msg) {
+ fd_store(socket, fd, fd_normal);
+ return 0;
+ }
+
+ ret = transpose_socket(socket, fd_rsocket);
+ if (ret < 0)
+ return ret;
+
+ real.close(fd);
+ return rconnect(ret, addr, addrlen);
+}
+
int connect(int socket, const struct sockaddr *addr, socklen_t addrlen)
{
struct sockaddr_in *sin;
int fd, ret;
- if (fd_get(socket, &fd) == fd_rsocket) {
+ switch (fd_get(socket, &fd)) {
+ case fd_fork:
+ return connect_fork(socket, addr, addrlen);
+ case fd_rsocket:
sin = (struct sockaddr_in *) addr;
if (ntohs(sin->sin_port) > 1024) {
ret = rconnect(fd, addr, addrlen);
rclose(fd);
fd = ret;
+ break;
+ default:
+ break;
}
return real.connect(fd, addr, addrlen);
va_end(args);
return ret;
}
+
+/*
+ * We can't fork RDMA connections and pass them from the parent to the child
+ * process. Intercept the fork call, and if we're the child establish the
+ * RDMA connection after calling fork. The assumption is that the last
+ * connection accepted by the server will be processed by the child after the
+ * fork call.
+ *
+ * It would be better to establishing the RDMA connection once the child
+ * process tries to use the connection after the fork call (i.e. in a read
+ * or write call), rather than making the previous assumption.
+ */
+pid_t fork(void)
+{
+ struct sockaddr_storage sa;
+ struct sockaddr_in6 sin6;
+ pid_t pid;
+ sem_t *sem;
+ int lfd, sfd, dfd, ret, param;
+ socklen_t len;
+ uint32_t msg;
+
+ init_preload();
+ pid = real.fork();
+ if (pid || !fork_support || (last_accept < 0) ||
+ (fd_get(last_accept, &sfd) != fd_fork))
+ goto out;
+
+ len = sizeof sa;
+ ret = real.getsockname(sfd, (struct sockaddr *) &sa, &len);
+ if (ret)
+ goto out;
+ sin6.sin6_family = sa.ss_family;
+ sin6.sin6_port = ((struct sockaddr_in6 *) &sa)->sin6_port;
+
+ sem = sem_open("/rsocket_fork", O_CREAT, 0644, 1);
+ if (sem == SEM_FAILED)
+ goto out;
+
+ lfd = rsocket(sa.ss_family, SOCK_STREAM, 0);
+ if (lfd < 0)
+ goto sclose;
+
+ param = 1;
+ rsetsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, ¶m, sizeof param);
+
+ sem_wait(sem);
+ ret = rbind(lfd, &sin6, sizeof sin6);
+ if (ret)
+ goto lclose;
+
+ ret = rlisten(lfd, 1);
+ if (ret)
+ goto lclose;
+
+ dfd = raccept(lfd, NULL, NULL);
+ if (dfd < 0)
+ goto lclose;
+
+ param = 1;
+ rsetsockopt(dfd, IPPROTO_TCP, TCP_NODELAY, ¶m, sizeof param);
+ set_rsocket_options(dfd);
+
+ msg = 0;
+ ret = real.write(sfd, &msg, sizeof msg);
+ if (ret != sizeof msg) {
+ rclose(dfd);
+ goto lclose;
+ }
+
+ copysockopts(dfd, sfd, &rs, &real);
+ real.shutdown(sfd, SHUT_RDWR);
+ real.close(sfd);
+ fd_store(last_accept, dfd, fd_rsocket);
+
+lclose:
+ rclose(lfd);
+ sem_post(sem);
+sclose:
+ sem_close(sem);
+out:
+ last_accept = -1;
+ return pid;
+}